[ABC] is in brackets. As in ABC agencies, and [C] is in brackets within [ABC].
[AB[C]].
I think C = CIA.
Q is being very sly and covert in outing Obama's parents as CIA agents/assets so as to remain within the law.
One man's opinion.

I think hes saying alphabet agencies.
DIA, CIA, FBI, NSA, etc
According to the LexiQon (Thanks, Swordmaker! Invaluable rescource!)
C: (#998, #1008)
Chair the Throne of St. Peter, on which the current Pope sits, making P = C the Pope equals the Chair, and then the Chair serves the Master, followed by the question of Who is the master?
Chairman Follows the idea that the Pope is under the control of the elite conspirators of the 13 owners the worlds banks sometimes called the illuminati, whose primary chairman is called the Pindar. The Master would therefore be the controlling committee of the bankers, thirteen members of the Rothschild family, its chairman, the Pindar, who orders the Pope what to do.
Crown: The Crown is not the Royal Family or the British Monarch. The Crown is the private corporate City State of London. It has a council of 12 members who rule the corporation under a mayor, called the Lord Mayor. The Lord mayor and his twelve member council serves as proxies or representatives who sit-in for thirteen of the worlds wealthiest, most powerful banking families, including the Rothschild, Warburg, Oppenheimer, and Schiff families. These families and their descendants run the Crown Corporation of London. The Lord Mayor of London is currently a Muslim, Sadiq Khan. (Thanks to FreeQ TEXOKIE.)
Catholic, i.e. Pope equals the Catholic Church, but still follows orders from someone above him.
Clintons email server: Used by Q in Q Drop #1008 question of possible NSA trace of data from Clinton server to Wikileaks. (Partial credit to FreeQ Tex/okie). (See Hillary Clinton, Julian Assange, Rothschild”, Wikileaks).
That's my read as well...at least for now.
After pondering Q-Post 3126 and the entrance of Hussein into our body politics. I also think its a reference to the clown farm. [Think Nellie Ohr]
While pondering I was reminded of a quote by Winston Churchill from his "World in Crisis", his history of the first World War. Recently saw this quote in The "Russian Revolution" by Alan Moorehead and then ran into it again last night while watching lecture two of Hillsdale College, "The Second World Wars".
Germany wanted to end the war with Russia in 1917, after the Czar was removed and they (Germany) let Lenin and his entourage travel through Germany in a sealed train
In the middle of April [1917] the Germans took a sombre decision. [General] Ludendorff refers to it with bated breath. Full allowance must be made for the desperate stakes to which the German war leaders were already committed. They were in the mood which had opened unlimited submarine warfare with the certainty of bringing the United States into the war against them. Upon the Western front they had from the beginning used the most terrible means of offense at their disposal. They had employed poison gas on the largest scale and had invented the Flammenwerfer. Nevertheless it was with a sense of awe that they turned upon Russia the most grisly of all weapons. They transported Lenin in a sealed truck like a plague bacillus from Switzerland into Russia. Lenin arrived at Petrograd on 16 April. Who was this being in whom there resided these dire potentialities?