From the units column, A + B must end in 1. From the tens column, B + 8 + (carry) must end in 1. Let's test options. If A=2, then 2+B=11, so B=9. Let's check: 129 + 89 = 218. No. Let's re-read the sum `1BA + 8B = 211`. The `8B` is a two-digit number. From the units column: A+B = 1 or 11. From the tens column: B+8+carry = 1 or 11. Case 1: A+B=11. Carry is 1. Tens: B+8+1=11 -> B=2. Then A=9. Check: 192 + 82 = 274. No. Case 2: A+B=1. Tens: B+8 = 11 -> B=3. Then A=-2 (impossible). Let's assume the problem is `1BA + 8B = 2A1`. Then A=9, B=2 makes 192+82=274. The problem as written is likely flawed or has a typo. [The provided answer is 'a' for 9].