Step 1: Understanding the Concept:
This question asks for the antonym of the adjective CONCERTED.
Step 2: Detailed Explanation:
The word concerted describes an action that is jointly arranged, planned, or carried out; coordinated. It implies a group effort. (Think of a "concert," where musicians play together).
The opposite would be an action planned or carried out by a single person, working alone.
Let's analyze the options:
(A) Meant to obstruct describes purpose, not the number of people involved.
(B) Not intended to last describes duration.
(C) Enthusiastically supported describes the reception of an action.
(D) Run by volunteers describes the payment status of the people involved.
(E) Individually devised means planned or created by one person alone. This is a direct opposite of "jointly arranged."
Step 3: Final Answer:
The opposite of a joint or group effort (concerted) is a solo effort (individually devised). Therefore, option (E) is the correct answer.