Which of these is true? All three can't be at the same time true as they are contradictory
Jesus would have explained what He meant to His disciples and Nicodemus who would have explained it down to THEIR disciples and so on and so forth ("ok, Druselius, now I was taught by Antonicus who was taught by Marius who was taught by Ignatius who was taught by Polycarp who was taught by John the Apostle who was taught by Jesus that this passage here means.....").
There is no doubt that Christ taught His disciples, scripture even points out that He taught them post His resurrection, yet those points are not in scripture, so what are they? Maybe a detailed set of what the words given earlier really meant? Most likely because the Apostles and the ones following them were always clear to say that they learnt from so-and-so Apostle
Paul made it clear when he says not to say "I am of Apollo, I am of Paul but of Christ" that the focus should be on the ultimate teacher of the teachers, not that he is against people sticking to the rule of what was taught by their teachers. In fact he urges people to stick to what they were taught and to hand that down to others. That is the basic definition of Holy Tradition -- the teachings from the Ultimate Teacher through a succession of teachers, all lesser -- it doesn't matter about the character of the intervening teachers, what matters is the Truth is pure and it is pure because it comes from the Ultimate Teacher who is pure.