Which visa type should be applied to invite my parents to USA in DS-160?

[patelniravec]

Hi I want to invite my parents to usa for my grad ceremony.

I am little bit confused in filling form ds-160's traveling section

what type should i select for visa? is it b-2 or b1/b2 visa as a sub category of B-visa?

Thanks

[ramabalaji]

B2 Tourism/Medical treatment