Correct Option
As per the 1991 Census, Pondicherry recorded a literacy rate of 75.3%, and Delhi recorded 74.7%. This combination represented the highest literacy rates among the Union Territories listed in the options for that census period.
Incorrect Options
Options (1), (2), and (3) include Union Territories such as Chandigarh, Dadra & Nagar Haveli, and Andaman & Nicobar Islands. In 1991, these UTs had literacy rates lower than those of Pondicherry and Delhi, thus not forming the group with the highest literacy rates. For instance, Dadra & Nagar Haveli had a significantly lower literacy rate of 40.7% in 1991.