A likert scale with an odd number of scale points between "strongly agree" and "strongly disagree":

(a) cannot have equal scale distances.

(b) cannot have a neutral middle point.

(c) must have a verbal label on each scale point.

(d) is often used in marketing surveys.

(d) is often used in marketing surveys.

Explanation:

A likert scale is a psychometric scale that is usually used in research using questionnaires. It is a 5 or 7 point scale that allows individuals indicate how they agree or disagree with something. For example

1- Strangely disagree

2- Disagree

3- Neutral

4- Agree

5- Strongly agree

The likert scale is often used in marketing surveys to get people's opinion on a subject matter with a view of improvement.

Let's say there is a customer survey that asks how satisfied a customer is, feedback from likert scale is used to improve on the service rendered by the company.

a) both were commissioned explorers