We get cotton from ______________________ of cotton plants. 

There are many goods around us that are derived from various sections of plants, which is why we rely on plants directly or indirectly. Cotton is an important fibre crop derived from cotton plants. Let's have a look at where we can get cotton.

Cotton is India's most significant fibre crop due to its wide range of applications in all areas. Cotton is a kharif crop that takes around eight months to mature. Cotton farming has been practised in India for centuries.
Cotton is obtained from the cotton plant's fruit. Cotton balls are the fruit of cotton plants. The cotton plant's fruit contains 32 immature seeds. These immature seeds mature and produce fully grown cotton fibre.

Within one month, the cotton ball develops and thickens, forming a hollow cotton fibre inside the cotton ball, which finally swells to the size of the figure over time. A cotton ball takes almost another twenty-five days to develop. It takes around 4055 days for a cotton ball to break and yield natural cotton as well as the segments.
The dried section (carpel) is known as the bur, and it is the bur that holds the cotton in place until it has entirely dried, grown, and developed and ready for harvesting.

Hence, we get cotton from the fruit of cotton plants.

Hence option A is correct.