In which of the plant species, parthenocarpy takes place?

The correct answer is Banana.

What is Parthenocarpy?
Parthenocarpy is a biological process in which fruits develop without prior fertilization of the ovules. Because no fertilization occurs, the resulting fruits are seedless (or contain non-viable seeds).

Detailed Explanation:
1. Banana (Musa species): Bananas naturally exhibit vegetative parthenocarpy. The fruit develops from the ovary without pollination or fertilization, leading to the familiar seedless commercial banana.
2. Mango, Peach, and Jackfruit: These fruits typically undergo normal pollination and fertilization to form seeds inside their fleshy fruit bodies (true fruits developed through sexual reproduction).

Therefore, among the given options, parthenocarpy takes place naturally in Banana.