Sight Distance of Vertical Parabolic Curve

I need help to this problem I wonder if the answers are in the following choices. The problem is.. A vertical parabolic curve, 135 m long has a tangent grades of -1.7% and 2.3% . Find the sight distance in m.
a. 139.6 c. 147.1
b. 149.8 d. 140.6

Akala ko plane geometry ang subject nito. Surveying and Traffic Engineering pala ang topic nyan.....hehehehehe

135=122+3.5S/ -1.7-2.3 ______ S=147.1