Correct Answer: A ÷ B × C

Solution : Let's check the options –
First option: A ÷ B + C
According to the given expression, the family tree will be as follows –

Here, the quadrilateral represents the male, and the circular figure represents the female in the figure. From the above family tree, it is evident that A is the paternal aunt of C.
Second option: C × B ÷ A
According to the given expression, the family tree will be as follows –

Here, the quadrilateral represents the male, and the circular figure represents the female in the figure. From the above family tree, it is evident that A is either the daughter or the son of C, as the gender of A is undefined.
Third option: A ÷ B × C
According to the given expression, the family tree will be as follows –

Here, the quadrilateral represents the male, and the circular figure represents the female in the figure. From the above family tree, it is evident that A is the maternal aunt of C.
Fourth option: B ÷ C × A
According to the given expression, the family tree will be as follows –

Here, the quadrilateral represents the male, and the circular figure represents the female in the figure. From the above family tree, it is evident that A is either the son or the daughter of C, as the gender of A is undefined.

So, only the expression in the third option satisfies the relation given in the question. Hence, the third option is correct.