Which three sentences correctly use parallel structure?

the topic i chose to write about was " why scuba diving is so popular". the topic is suitable for the audience because it is the easiest to develop and explain, it can be explained in a simpler more conversational manner, it does not require the use of too many technical words, and the final reason for selecting this topic is that it is the one most people can relate to, you might not know too much about scuba diving, but you could probably agree that it is very popular. the purpose of the writing about this topic is to convince more people about the benefits both for the body and the mind that   scuba diving can have on a person. it can you keep fit since it requires a lot of energy when swimming underwater; it also you relax because you forget about the world when you are underwater being mesmerized by the underwater world. i would write this paper in the summer, a perfect time to give scuba diving a try if a person has not done it yet.

this forms a narrow, steep sided inlet (sometimes deeper than 1300 metres) connected to the sea. the terminal moraine pushed down the valley by the glacier is left underwater at the fjord’s entrance, causing the water at the neck of the fjord to be shallower than the main body of the fjord behind it.

b is correct

have a cool day