The angle of projection of a particle is measured from the vertical axis as $$\phi$$ and the maximum height reached by the particle is $$h_m$$. Here $$h_m$$ as function of $$\phi$$ can be presented as

given
angle φ is measured from vertical

so convert to usual projectile angle θ (from horizontal):

θ = 90° − φ

maximum height formula:

hₘ = (u² sin²θ) / (2g)

substitute θ:

hₘ = (u² sin²(90° − φ)) / (2g)

use identity:

sin(90° − φ) = cosφ

so,

hₘ = (u² cos²φ) / (2g)

so relation is:

hₘ ∝ cos²φ

now understand behavior of cos²φ

when φ = 0°
cosφ = 1 → hₘ is maximum

when φ increases
cosφ decreases → hₘ decreases

when φ = 90°
cosφ = 0 → hₘ = 0

so graph must:

start at maximum value at φ = 0
decrease continuously
reach zero at φ = 90°

shape:

cos²φ decreases slowly at first, then faster
so curve is downward bending (not straight)

check options:

A → increasing → wrong
B → goes up then down → wrong
C → starts high, smoothly decreases to zero → correct
D → decreases too sharply like exponential → wrong

final answer: C