Work backward from a word you already know is correct: the singular of "scarves" is "scarf," the same pattern as "knife" becoming "knives" or "leaf" becoming "leaves," where "fe" or "f" turns into "ves" in the plural.
Now compare that known spelling, "scarf," against the three choices. "Scarve" is missing the correct ending, "scarfe" has an extra silent letter, and "scarv" is missing the "f" sound entirely. None of them match "scarf" exactly.
Since the actual word is not listed, the right answer is D, none of the above.