Final answer:
The measure of angle A is 100°, as alternate interior angles formed by parallel lines and a transversal are congruent. Option c is correct.
Step-by-step explanation:
To find the measure of angle A, we need to use the fact that James Road and River Road are parallel. When two parallel lines are intersected by a transversal, the alternate interior angles formed are congruent.
Therefore, angle A is congruent to the angle formed by the transversal, which is equal to 100°.
Thus, the measure of angle A is 100°.
Hence, The measure of angle A is 100°, as alternate interior angles formed by parallel lines and a transversal are congruent. Option c is correct.