The problem given below consists of a question and two statements numbered I and II. You have to decide whether the data provided in the statements are sufficient to answer the question.
How many sisters does Sunny have ?
I. Sunny is the only son of his parents.
II. Sunny's parents have three children.

Correct option is C

Statement I tells us that Sunny is the only son of his parents, but it does not provide any information about Sunny's sisters, making it insufficient on its own.
Statement II states that Sunny's parents have three children, but it does not provide specific details about the gender of the children, making it insufficient on its own as well.
Combining both statements, we know that Sunny is the only son and his parents have three children, which means Sunny has 2 sisters. Therefore, Statements I and II together are sufficient to answer the question.