Assertion (A) : `CO_2` is a gas but `SiO_2` had a three -dimenstional network structurte .
Reason (R): `CO_2` bonds nut `SiO_2` has a three-dimensional network structure .
A. If both (A) and (R) are correct and (R) is correct explanation of (A)
B. If both (A) and (R) are correct and (R) is not correct explanation of (A)
C. If (A) is correct , but (R) is incorrect
D. If (A) is incorrect but (R) is correct .
