Verified Answer :

ElYellowFlower

The noun Sky is not an abstract noun. 
Sky is a concrete noun. A concrete noun is a word for something that can be seen, heard, felt, tasted or smelled. 

olemakpadu

An abstract noun is a noun form in which the material form is not tangible, it is not in the form of a substance.

Therefore Truth is abstract, so is Beauty and Faith.

But Sky is not an abstract noun.  It has a material form.

So option B is the correct one.

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