Incapable of being seen through

A. Ductile

B. Opaque

C. Obsolete

D. Potable

Answer: Option B

Solution(By Examveda Team)

One word substitute is Opaque.

Ductile: (of a metal) able to be drawn out into a thin wire.
Opaque: not able to be seen through.
Obsolete: no longer produced or used.
Potable: safe to drink.