Concept:
An uncle is the brother of one’s parent. To verify this, we need to establish a clear relationship between individuals.
Step 1: Analyze Statement I alone.
‘P’ is the brother of ‘M’.
‘M’ is the father of ‘Q’.
Thus, ‘P’ is the brother of Q’s father $\Rightarrow$ P is the uncle of Q.
Statement I alone is sufficient.
Step 2: Analyze Statement II alone.
Gives information about siblings of Q, but nothing about P.
Statement II alone is NOT sufficient.
Step 3: Combine both statements.
Not required, since Statement I alone is sufficient.
Hence, Statement I alone is sufficient.