In a certain code language,
'A + B' means 'A is the daughter of B',

'A - B' means 'A is the brother of B',

'A × B' means 'A is the mother of B'.

Based on the above, how is K related to O if 'K-L × M-N + O'?

Let's decode the given expression 'K-L × M-N + O' step-by-step from left to right:
K - L: K is the brother of L (K
(+)
−L).

L × M: L is the mother of M (L
(−)
is parent of M).

M - N: M is the brother of N (M
(+)
−N). Since L is the mother of M, L is also the mother of N.

N + O: N is the daughter of O (N
(−)
is the child of O). Since L is already known to be the mother of N, O must be the father of N, making L and O a married couple (L
(−)
⇔O
(+)
).

Now we need to determine how K is related to O:

L is the wife of O.

K is the brother of L.

Therefore, K is the brother of O's wife, which means K is O's Wife's brother.