The problem asks us to identify the acute angles in the given diagram. An acute angle is an angle that is greater than $0^\circ$ and less than $90^\circ$.

1. Problem Description

The problem asks us to identify the acute angles in the given diagram. An acute angle is an angle that is greater than $0^\circ$ and less than $90^\circ$.

2. Solution Steps

We need to examine each angle in the diagram and determine if it is acute.

- $\angle A$: This angle appears to be less than $90^\circ$, so it is an acute angle.

- $\angle B$: This angle appears to be greater than $90^\circ$, so it is not an acute angle. It is an obtuse angle.

- $\angle C$: This angle appears to be less than $90^\circ$, so it is an acute angle.

- $\angle D$: This angle appears to be greater than $90^\circ$, so it is not an acute angle. It is an obtuse angle.

3. Final Answer

$\angle A, \angle C$