The answer is A. The Y chromosome doesn't experience crossing-over.
The crossover of chromosomes is the exchange of genetic material between homologous chromosomes. In males, X and Y chromosomes pairs but they cannot exchange genetic material except at the ends of the chromosomes called pseudoautosomal regions. So, greatly, the Y chromosome doesn't experience crossing-over.
Through the process of elimination:
B. A mother gives X chromosome and a father gives Y chromosome to the son.
C. The mitochondria cannot be passed in the nucleus of a cell since it is another organelle.
D. It is thought that mitochondria is passed only from mother to her offspring, so they cannot vary greatly.
