AMC 10A 2012 Problem 4

Past Contests AMC 10 2012 Part A
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1

Let \angle A B C=24^{\circ} and \angle A B D=20^{\circ}. What is the smallest possible degree measure for \angle C B D ?

Answer Choices
A. 0
B. 2
C. 4
D. 6
E. 12