The Maternal Genes Restrict the Expression of Paternal Homolog Analysis

I’m working on a genetics question and need an explanation and answer to help me learn.

You cross a female homozygous recessive Igf2 dwarf mouse with a male
homozygous dominant Igf2 normal sized mouse and see all progeny are dwarf. The
reciprocal cross is done (female homozygous dominant normal sized and male
homozygous recessive dwarf) and all the progeny are normal sized. What is going on?
A) This demonstrates dominant epistasis
B) This demonstrates recessive epistasis
C) The maternal homolog is imprinted and silenced
D) The paternal homolog is imprinted and silenced