Explanation:

To understand the concept of acute angles, let's first define what an angle is.

Definition of an Angle:
An angle is formed when two rays share a common endpoint. The common endpoint is called the vertex, and the two rays are called the sides of the angle.

Definition of an Acute Angle:
An acute angle is an angle that measures less than 90 degrees. It is smaller than a right angle (90 degrees) and larger than a straight angle (180 degrees). In other words, an acute angle falls within the range of 0 to 90 degrees.

Now, let's analyze the given options and determine which one represents the range of an acute angle.

a) 180 to 180:
This range is not valid for an acute angle because it represents a straight angle, which measures exactly 180 degrees. A straight angle is larger than an acute angle, so this option is incorrect.

b) 0 to 90:
This range represents the valid range for an acute angle. It starts from 0 degrees and goes up to 90 degrees, which is smaller than a right angle. Therefore, this option is correct.

c) 90 to 180:
This range represents the valid range for an obtuse angle, not an acute angle. An obtuse angle measures between 90 and 180 degrees. Since an obtuse angle is larger than a right angle, it is also larger than an acute angle. Therefore, this option is incorrect.

d) 0 to 45:
This range is narrower than the valid range for an acute angle. An acute angle can measure up to 90 degrees, so limiting it to 45 degrees only would exclude angles between 45 and 90 degrees. Therefore, this option is incorrect.

Conclusion:
The correct answer is option 'B' (0 to 90). This range represents the valid range for an acute angle, which measures less than 90 degrees.

Angles under 90 degrees are acute angles