Study the following information carefully and answer the question given below:
'P, Q' means 'P is mother of Q'
'P+Q' means 'P is father of Q'
`'Pxx Q'` means 'P is sister of Q'
'P-Q' means 'P is brother of Q'
What will come in place of question mark to establish that N is father of T in the following expression?
N+R?SXT

Options

A. only `'xx'`
B. only -
C. Either '-' or `'xx'`
D. cant not be determined

Answer

C

Explanation

Hence, R is either brother or sister of S.