I read the law (or was it in the Constitution?) a while back, and as I recall, you can challenge any single elector. I will have to go back and read it again before the 6th.
ThanQ...I was wrong. You both are exactly right.
Besides the Constitution,(in a lot of cases doesn't provide context ) I use this research document:(which just recently has been revised) and right on point here:
https://fas.org/sgp/crs/misc/RL32717.pdf"In 1969, a Representative (James O’Hara of Michigan) and a Senator (Edmund S. Muskie of Maine) objected in writing to counting the vote of an elector from North Carolina who had been expected to cast his vote for Richard Nixon and Spiro Agnew, but who instead cast his vote for George Wallace and Curtis LeMay. Both chambers met and voted separately to reject the objection, so when the joint session resumed, the challenged electoral vote was counted as cast.(13) In that instance, the elector whose vote was challenged was from a state that did not by law bind its electors to vote only for the candidates to whom they were pledged." then look at footnote #13.
13 When the two chambers reconvened in joint session, the Secretary of the Senate reported that the Senate had agreed to the following action: “Ordered, that the Senate by a vote of 33 ayes to 58 nays rejects the objection to the electoral votes cast in the State of North Carolina for George C. Wallace for President and Curtis E. LeMay for Vice President.” The Clerk of the House stated the results of the House action: “Ordered, that the House of Representatives rejects the objection to the electoral vote of the State of North Carolina submitted by the Representative from Michigan, Mr. O’Hara, and the Senator from Maine, Mr. Muskie.” Congressional Record, vol. 115 (January 6, 1969), p. 171. The House vote was 170-228. See also Deschler’s Precedents, vol. 3, chap. 10, §3.6. Both houses used roll call votes to decide the question. and I use the Electoral Count Law as a guide.
https://www.law.cornell.edu/uscode/text/3/chapter-1