Step 1: Analyzing Statement I.
- \( H \) is married to \( P \).
- \( P \) is the mother of \( T \), making \( H \) the father of \( T \).
- \( T \) is married to \( D \), and \( D \) is the father of \( B \), making \( T \) the mother of \( B \).
- Since \( H \) is \( T \)'s father, \( H \) is B’s grandfather.
Step 2: Analyzing Statement II.
- \( B \) is the daughter of \( T \).
- \( T \) is the sister of \( N \).
- \( H \) is the father of \( N \), which means \( H \) is also the father of \( T \).
- Since \( T \) is \( B \)'s mother, \( H \) is \( B \)'s grandfather.
Thus, either statement alone is sufficient.