Glenda, Helga, Ioana, Julia, Karl, and Liu participated in the 2017 Canadian Team Mathematics Contest. On their team uniforms, each had a different number chosen from the list 11, 12, 13, 14, 15, 16. Helga's and Julia's numbers were even. Karl's and Liu's numbers were prime numbers. Glenda's number was a perfect square. What was Ioana's number?
(A) 11
(B) 13
(C) 14
(D) 15
(E) 12
Of the given uniform numbers,

- 11 and 13 are prime numbers
- 16 is a perfect square
- 12, 14 and 16 are even

Since Karl's and Liu's numbers were prime numbers, then their numbers were 11 and 13 in some order.

Since Glenda's number was a perfect square, then her number was 16 .

Since Helga's and Julia's numbers were even, then their numbers were 12 and 14 in some order. (The number 16 is already taken.)

Thus, Ioana's number is the remaining number, which is 15 .

ANSWER: (D)