Statement I tells us that the park has less than 3 children, which means the number of children is either 1 or 2.
Statement II tells us that the number of children is odd, which means the number of children is 1.
Combining both statements, we deduce that the number of children in the park is 1.
Therefore, both Statement I and Statement II together are sufficient to answer the question.
The correct answer is (a) Both statements I and II together are sufficient.