Final answer:
A cross-cousin is the child of your mother's brother or your father's sister; thus, the correct answer is C: your mother's brother's son.
Step-by-step explanation:
In the context of kinship terms and relationships, a cross-cousin is your cousin through your parents' opposite-sex siblings. This means that your cross-cousins are the children of your mother's brother (your maternal uncle) or your father's sister (your paternal aunt). Therefore, the correct answer from the choices given would be C: your mother's brother's son. This individual is your cross-cousin because he is the child of your mother's brother. In many cultures, the relationship with cross cousins is distinct from the relationship with parallel cousins—those who are children of your parents' same-sex siblings (e.g., your mother's sister's daughter or your father's brother's son).