Ans is A
Statement 1 tells that PQ=x, QR=x+2, and PR=x+3
So PR is the largest side and the angle that lies against PR has to be the largest.

SUFF

Statement 2 tells us that x=2, but tells us nothing about y, so we can't evaluate the length of PR.

INSUFF

In a triangle, longest side has biggest degree. Only I show us that y > x. So I choose A

I think its C i.e. both are required

1) y = x + 3 lets say x = 1, so sides will be 1,3,4 and which I think violates rule "Sum of lengths of two sides should be greater than other side so here 1+3 is not > 4

but with X =2 alone we dont know y hence together
1) & 2)
if x = 2 then sides will be 2, 4, 5 sufficient to make a triangle and then angle opposite largest size is largest

correct me BTG experts I may be wrong

The answer is A

1) y = x + 3 lets say x = 1, so sides will be 1,3,4 and which I think violates rule "Sum of lengths of two sides should be greater than other side so here 1+3 is not > 4

Why are you assuming anything about Y??
Since this is a question of DATA sufficiency, you are not advice to add data on your behalf to complete the question.

The answer is A

I can't convince myself, may I know the source of question?

The question asks us to point which is the largest degree, we don't have to give the number, so I is enough. With II we can give the result but it is not necessary this time.