Why did the author write this passage?

Responses
A to explain how seaplanes are usedto explain how seaplanes are used
B to persuade people that seaplanes are importantto persuade people that seaplanes are important
C to encourage people to take a ride in a seaplaneto encourage people to take a ride in a seaplane
D to help people understand how seaplanes are built

A to explain how seaplanes are used