Task: Question Answering
Input (English): Question: If a and b are different positive integers and a + b+1 = a(a + b), then which of the following must be true?
I. a = 1
II. b = 1
III. a < b

 Option A: I only

 Option B: II only

 Option C: III only

 Option D: I and II

 Option E: I and III
Output (English): Option D