1. The problem asks to write the given expression in lowest terms. 2. To determine if the expression can be simplified, we need to check if there are any common factors in the numerator and denominator that can be canceled. 3. Since the options are expressions like $a - y$, $-1$, $a + y$, or "Already in lowest terms", we must identify the original expression to simplify. 4. Without the original expression provided, we analyze the options: - Option A: $a - y$ - Option B: $-1$ - Option C: $a + y$ - Option D: Already in lowest terms 5. If the original expression matches one of these and cannot be simplified further, then Option D is correct. 6. Since no original expression is given, the safest conclusion is that the expression is already in lowest terms. Final answer: Option D: Already in lowest terms