Sleight of hand,
also known as prestidigitation or legerdemain, are a set of techniques used by a magician to manipulate objects such as cards and coins secretly
"are" is incorrect because "Sleight of hand " is singular (A) & (E) out
"such as " is correct because cards and coins are quoted as examples. (E) & (C) out
Lets compare (B) & (D)A. also known as prestidigitation or legerdemain, are a set of techniques used by a magician to manipulate objects such as cards and coins
B. also known as prestidigitation or legerdemain,
is a set of techniques used by a magician to manipulate objects such as cards and coins
"is" makes the sentence clear and structurally correct.C. also known to be prestidigitation or legerdemain, is a set of techniques used by a magician to manipulate objects like cards and coins
D. which is also known as prestidigitation or legerdemain, a set of techniques used by a magician to manipulate objects such as cards and coins
no problem in using "which" but the lack of " is" makes the sentence unclear and structurally incorrectE. also known as prestidigitation or legerdemain, are a set of techniques used by a magician to manipulate objects like cards and coins