Step 1: Understand the role of supervision.
Supervision involves overseeing employees’ activities to ensure that they are performing their tasks as per the organizational objectives.
Step 2: Evaluate the options.
- Supervision is necessary to ensure that employees are working efficiently and adhering to company standards.
- It is not unnecessary, as proper supervision leads to higher productivity and reduces mistakes.
- Wastage of time is not correct, as supervision aims to enhance performance, not waste time.
Step 3: Conclude.
Supervision is an essential function of management to ensure effective task completion.
Final Answer:
\[
\boxed{\text{Necessary}}
\]