You are given a geometric mathematical question. Questions in this task often involve shapes and Geometric Relationships. You are also given 4 or 5 answer options (associated with "A", "B", "C", "D", "E"). Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'. LaTeX mathematical format (the standard way to express mathematical expressions in the typesetting software known as LaTeX) is used to express equations. Each question is solvable with high school math knowledge.

Ex Input:
If the perimeter of a regular polygon is 21, which of the following could be the length of one side of the polygon?
(A)6 (B)5 (C)4 (D)3 (E)2

Ex Output:
D


Ex Input:
In \(\triangle { ABC } \) two sides, AB and BC are equal. Side AC has a length of 5, and the perimeter of \(\triangle { ABC } \) is 13. If the measure of angle ABC is \(x\), which of the following must be true about \(x\)?
(A)\(x < 60\) (B)\(60 < x < 90\) (C)\(x = 90\) (D)\(x > 90\) (E)It cannot be determined from the information given.

Ex Output:
B


Ex Input:
In \(\triangle { ABC } \), \(\overline { AB } = \overline { BC } \) and \(\overline { AB } \perp \overline { BC } \). If \(\overline { BC } = 10\), what is the area of the triangle?
(A)\(10 \sqrt { 2 } \) (B)25 (C)50 (D)\(50 \sqrt { 2 } \) (E)100

Ex Output:

C