Answer :
"A. Swift was satirizing the problems that ensued after an influx of French
Catholics into Protestant England" is correct, although this wasn't his only intent.
In Gulliver's Travels, Swift satirizes different aspects of English society. He discuses different problems society faces and criticizes how the country is governed. The author depicts the problems in a different context each time that each voyage takes place in a different place and in a different form. He just tries to describe the problems of the society through fairy-tale, satirizing the aspects like politics, literature, philosophy and literature. Therefor, the correct answer is D.