Is it trump/obama/biden??!
The form of writing that is needed in this case IS ESSAY and the kind of supporting details suitable for this audience and purpose are DETAILS THAT SUPPORT THE MAIN IDEA.
This type of essay writings called academic writing. Academic writing usually use formal language and the work have to be referenced because other source are always used in putting this type of writing together.
I am not sure I understand your multiple choices for answers, but the correct words to put into your sentence are: 'explains', and 'is'. Because the word 'either' has been used, that changes the the word after lantern from multiple to singular.
Washington Irving was the first American author who found success both in Europe and in America. He's actually considered the father of American literature because it is his writing that began shaping the American identity.