CONCEPT: The question is a word problem from arithmetic.
-To ensure that at least 10 beans selected are of the same color-
Choose 9 beans of BLACK
Choose 9 beans of BLUE
Choose 9 beans of GREEN
Hence total ways =9*3 +1 =28 to ensure a bean of each colour.
[9+9+9 to ensure you have 9 beans of each colour and the last 1 bean will complete the need of the question].Hence (A)