This question is easy. . . It's actually shows you what the correct answer is. . .
The answer to this is C:
EXPLANATION:
Because A doesn't make sense. when you put That is Alex, whom I was telling u about. And B, it's does kinda make sense when you put who in a sentence. And C, does make sense when you put That is Alex, ''which" I was telling u about. Because, I pick C because I think it's make way more sense more then the other answers. . .
