I think it is B. Hope this helps!
So, angles A and B added together is 130° which makes the whole angle = 180°-130°=50°
The answer is 180° because it is a supplementary angle and all supplementary angles equal 180° so, all the angles added makes 180°
It is 391 because 1+0=1, 9+0=9, and 1+2=3
He could buy 6 combinations of stickers