Answer:
Explanation:
An acute angle measures between 0° & 90°, i.e., it's smaller than 90° (right angle) but greater than 0°.
An obtuse angle measures between 90° & 180°, i.e., it's greater than a right angle but smaller than a straight angle.
A right angle is exactly 90° & is the perfect half of a straight angle (180°, angle of a straight line).
A straight angle is exactly 180° & is the perfect half of a complete angle (360°; angle around a point).
From this information, we can say that, the correct answer to the given question is a. Acute.