A={2,3,5,7,11,13,17,19........}
B={2} ($\because$ 2 is the only even prime.Because,if any other prime is divisible by 2, then it is not prime)
C={3,5,7,11,13,17,19,23....} ($\because$all primes except 2 are odd.)
1-True.It can be clearly seen that $A= B \cup C$
2-True.Since,B has only 1 element.
3-True .$\because$ C need only one element 2 to become A.
$\therefore$all the statements are true.
Hence option D