Horizontal distance between
A and
B = (100 - 95)/0.05 = 100 m
Horizontal distance between
B and
C = (100 - 97)/0.03 = 100 m
The figure above placed the parabolic curve at the middle-half:
$\text{Elev } PC = \text{Elev } A + 50(0.05)$
$\text{Elev } PC = 95 + 2.5$
$\text{Elev } PC = 97.5 \, \text{ m}$
Distance from PC to the summit:
$\dfrac{S_1}{0.05} = \dfrac{100}{0.08}$
$S_1 = 62.5 \, \text{ m}$
Elevation of the summit:
$\text{Elevation of the summit} = \text{Elev } PC + \frac{1}{2}S_1(0.05)$
$\text{Elevation of the summit} = 97.5 + \frac{1}{2}(62.5)(0.05)$
$\text{Elevation of the summit} = 99.0625 \text{ m}$ [ B ] answer