Final answer:
The measure of ∠B in triangle A'B'C' is the same as the measure of ∠B in triangle ABC. Hence the correct answer is option A
Step-by-step explanation:
In order to determine the measure of ∠B in triangle A'B'C' after it has been translated 5 units to the right and 4 units up from triangle ABC, we need additional information. The translation of a triangle does not alter the measures of its angles. Therefore, the measure of ∠B in triangle A'B'C' is the same as the measure of ∠B in triangle ABC.
Hence the correct answer is option A