The correct option is C Dizygotic twins
Sometimes, there are two eggs released by the ovary. Fertilisation of both eggs by two different sperms results in two zygotes leading to birth of dizygotic twins. Here, Jack and Jill are both of different gender which is possible only if they are dizygotic.
Monozygotic twins are formed from a single zygote and both individuals will always be of same gender.
Siamese twins also known as conjoined twins, are also formed from a single zygote. Hence, will be of same gender.