Given:
initial angular speed, 
= 21.5 rad/s
final angular speed, 
= 28.0 rad/s
time, t = 3.50 s
Solution:
Angular acceleration can be defined as the time rate of change of angular velocity and is given by:
Now, putting the given values in the above formula:
Therefore, angular acceleration is:
The term which is considered as being undefined is referred to as a point and is therefore denoted as option A in this context.
<h3>What is a Point?</h3>
This is defined as as small round mark written on a plane which signifies the position or location of a substance. This can also be seen as a dot and is also used to separate a group of numbers such as in the case of decimals etc.
It is referred to as being undefined alongside a plane, line etc as a result of it only being explained using specific examples and descriptions unlike a segment which can be viewed and understood easily when working on the parameter.
This is therefore the reason why a point is undefined and the most appropriate choice.
Read more about Point here brainly.com/question/17206319
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Ok, now what do you want to know about it?
