Correct option (d) +1
Explanation:
Lewis gave the structure of O3 molecule as
Using the relation,
Formal charge =[Total no. of valence electrons in the free atom] - [Total no- of non-bonding (lone pair) electrons] -1/2 [Total no. of bonding (shared) electrons]
The formal charge on central O atom i.e., no. 1 = + 1