He has bought genuine pearls.

Answer: Option C

Genuine : truly what something is said to be; authentic.
Inexpensive : not costing a great deal; cheap.
Unattractive : not pleasing or appealing to look at.
Spurious : not being what it purports to be; false or fake.
Extraneous : irrelevant or unrelated to the subject being dealt with.

Antonym of Genuine is Spurious