Step 1: Approach
Test the four input pairs.
Step 2: Test
00 gives 0. 01 gives 1. 10 gives 1. 11 gives 1 (since $1+1=1$ in Boolean algebra).
Step 3: Answer
The output exists when A exists, or B exists, or both exist. Option (D).
Final Answer:
Y is 1 when A, or B, or both are 1, so it is an OR gate, option (D).
\[ \boxed{\text{Y exists when A or B or both exist}} \]