What is the reason for this error?

A developer receives a 401 Unathorized HTTP status message from a REST API request.

What is the reason for this error?
A . The account lacks the privileges necessary to perform the request
B. The access token was not found in the request, or it is invalid or expired
C. OAuth is not supported for the requested resource
D. API requests are temporarily blocked due to too many concurrent requests.

View Answer

Answer: B