Correct option is D
Series: SUMA, ASUM, MASU, ?
First term (SUMA): The original term is "SUMA".
Second term (ASUM): The last letter A moves to the front, resulting in "ASUM".
Third term (MASU): The last letter M moves to the front, resulting in "MASU".
Fourth term: Following the same rule, the last letter U should come to the front.
So, MASU becomes UMAS.
Correct answer is (d) UMAS.