a) The angle sum of a nondegenerate spherical triangle must be larger than 180 degreees, and I have a good reason why.

b) The angle sum of a nondegenerate spherical triangle must be larger than 180 degreees, but I am unsure of why.

c) AAA implies congruence on the sphere for nondegenerate triangles, and I have a good reason why.

d) Both a) and c)

e) Other