Task: Question Answering
Input (English): Question: The positive difference between Sam and Lucy’s ages is a, and the sum of their ages is z. If Lucy is older than Sam, then which of the following represents Lucy’s age?

 Option A: (z - a

 Option B: a - z/2

 Option C: 2a + z

 Option D: (z + a

 Option E: (a - z
Output (English): Option D