Note : In the following questions a statement of assertion followed by a statement of reason is given. Choose the correct answer out of the following choices.

Assertion : Network polymers are thermosetting.

Reason : Network polymers have high molecular mass.

Extensive linkage causes the formation of the three-dimensional network linkage in the polymer.

The polymer with an extensive linkage has many molecules linked to each other thus the molecular mass increases.

These types of polymers are infusible, hard and insoluble.

Thus, both the assertion and the reason are correct but the reason is not the correct explanation of the assertion.