Examine the words and/or phrases below and determine the relationship among the majority of words/phrases. choose the option that does not fit the pattern:
a) chert
b) rock salt
c) agate
d) flint

B) rock salt

Explanation:

Rock Salt is the composition of primarily the compound sodium chloride . Rock salt is the chemical sedimentary rock , which is composed by the process of evaporation of the ocean water .

But ,

Chert , Agate and  Flint , are the different varieties of silicon dioxide .

Hence , from the given options , the Rock salt is the option that does not fit the pattern .

81 is a composite number.