In Some Rare Salamander Species, All Individuals Are Females

In some rare salamander species, all individuals are females. Reproduction relies on those females having access to sperm from males of another species. However, the resulting embryos receive no genetic contribution from the males. Given this information, what is the role of sperm in reproduction in this species?

A) The sperm allow morphogenesis to proceed.
B) Sperm trigger egg activation.
C) Cell differentiation is initiated by the sperm.
D) Sperm are necessary to produce a diploid zygote.