Question

Which answer is correctly punctuated?

Mexican food in my opinion is the most flavorful.
Mexican food, in my opinion, is the most flavorful.
Mexican food in my opinion, is the most flavorful.
Mexican food, in my opinion is the most flavorful.

Answer 1

The second one.
Mexican food, in my opinion, is the most flavorful.
This one has the subject - Mexican food
a clause - in my opinion
and the predicate is most flavorful. 
Hope this helps. 

Answer 2

Answer:

Mexican food, in my opinion, is the most flavorful.