‘R8S’ means ‘R is the father of S’.
‘R7S’ means ‘R is the sister of S’.
‘R6S’ means ‘R is the brother of S’.
‘R2S’ means ‘R is the wife of S’.
Which of the following expressions represents ‘X is the mother of Y’?

A

X8M2Y

B

X2M8O2Y

C

X2M8Y

D

X7M6O2Y