Triangles ABD and CBD are shown.

Triangle A C D is divided into two smaller triangles which are triangle A B D and D B C which share a common side B D. Point B lies on segment A C. Segment A B is congruent to segment B C.

If m∠ABD = 100°, what is the relationship between AD and CD?

AD + DC < AC
CD = AD
CD > AD
CD < AD