Answer:
the answer is a.
Step-by-step explanation:
The order in which gifts are received doesn't matter - if child X gets toy 1 then toy 2, it's the same as giving child X toy 2 then toy 1 - so we are counting combinations.
The eldest child receives 3 of the 7 gifts, so they have

possible choices of gifts.
The next child receives 2 of the remaining 4 gifts, so they have

choices.
The last child receives the remaining 2 gifts, and there is only

way to select the gifts for them.
By the multiplication using, the total number of ways of distributing 7 gifts among 3 children in the prescribed way is 35 • 6 • 1 = 210.
Since it is a horizontal line with both Y's at 3 ( second number inside each set of parenthesis) we know the mid point is (X, 3)
to find the midpoint of X add the 2 values and divide by 2:
-2 + 10 = 8
8 / 2 = 4
so the midpoint is (4,3), the answer is D