From I alone: -
The heaviest person is also the 2nd shortest. A is heavier than C, who is shorter than B but not shortest.
So, neither B nor C is the 2nd shortest.
D is the lightest.
So, we get: -
Weight | Height |
A (Heaviest) | B (Tallest) |
| C |
| A |
D (Lightest) | D (Shortest) |
So, A is the heaviest.
From II: -
The 2nd shortest person is the heaviest person. C is lighter than B, who is the tallest.
Since, C is lighter than B. So, C is either shortest or 2nd tallest person.
So, we get: -
Weight | Height |
(Heaviest) | B (Tallest) |
| C/ |
| |
(Lightest) | C/ (Shortest) |
A is heavier than D.
Here, neither B nor C is the heaviest. Also, D cannot be the heaviest.
So, A must be the heaviest person.
So, we get: -
Weight | Height |
A (Heaviest) | B (Tallest) |
| C/D |
| A |
(Lightest) | D/C (Shortest) |
So, statement II alone is sufficient to answer the question.