Hi there,

YES , you can choose AR category (as second option) along with CE category.

However, you can also choose ES (Environmental Science and Engineering) as your second option.

Only a few colleges in India offer some specializations in Architecture to CE students through GATE AR.

Kindly check here for the combinations : Paper combinations GATE 2021 (https://gate.iitb.ac.in/papers.php)

Hope this helps..

Good Luck !!