Pretty sure its D
Hope this helped! :)
Flowers for Algernon is the title of a science fiction short story and a novel by American writer Daniel Keyes. The short story, written in 1958 and first published in the April 1959 issue of The Magazine of Fantasy & Science Fiction, won the Hugo Award for Best Short Story in 1960.[2] The novel was published in 1966 and was joint winner of that year's Nebula Award for Best Novel (with Babel-17).
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The following that is a modifier is C, an adjective and an adverb.
