Option C is the correct answer.

Your weight is a product of your mass (m) and the acceleration due to gravity (g) at that place. As we know, the magnitude of the acceleration due to gravity (g) decreases as we move toward a higher altitude, one weighs the most in the area that has the lowest altitude from the Earth's surface.

Out of the options given, Kechnakwal of Jhapa lies in the plains of Terai (Nepal). The other three options are the names of the Hills and the Himalayas which lie at a greater altitude than Japa. Therefore, you weigh the most in Jhapa.