In this idiom based question, you must choose the option that best explains the meaning of the expression back to the drawing board. This idiom is often used in professional, academic, and everyday situations when a plan has failed and a fresh start is needed.

Introduction / Context:
This question tests your knowledge of the common English idiom back to the drawing board. The phrase comes from the image of an engineer or designer returning to the drawing board after a design fails. In modern English, it is used metaphorically to indicate that a plan, idea, or attempt has not worked and that one must start again from the beginning with a new plan. Understanding such idioms is essential for interpreting conversations, news reports, and workplace communication.

Given Data / Assumptions:

• The idiom to be interpreted is back to the drawing board.
• Four possible meanings are provided, covering ideas of failure, fate, wasted effort, and returning to roots.
• Only one option correctly reflects the widely accepted meaning of the idiom.
• The context is general and may apply to business, projects, studies, or personal plans.
• You must select the option that fits the idiom as used in natural English.

Concept / Approach:
Idioms often come from specific images or professions but develop a broader usage. The drawing board represents the place where initial plans are sketched. If a design fails in practice, the designer goes back to the drawing board to create a new plan. Thus, the idiom back to the drawing board means that a current attempt has failed and one must start planning again. It does not inherently discuss destiny, wasted effort because of one mistake, or returning to one's roots, although failure may be involved.

Step-by-Step Solution:
Step 1: Read option (a) An idea has been unsuccessful and that a new one must be devised. This clearly captures the sense of failure of the present idea and the need to create a new plan from the start. Step 2: Read option (b) A person decides his own fate. This is about personal responsibility and free will, which is unrelated to the idiom. Step 3: Read option (c) All efforts can be wasted because of one mistake. This focuses on wasted effort, which can sometimes be a result of failure, but it does not mention the need to start planning again. Step 4: Read option (d) One always returns to his roots in times of crisis. This suggests going back to origins or original home, which is not part of the idiom's meaning. Step 5: Compare all options and note that only option (a) directly expresses the idea of abandoning a failed plan and creating a new one.

Verification / Alternative check:
Consider example sentences like The project was rejected by the client, so it is back to the drawing board for us. Here, the clear implication is that the present design has failed and a new design must be prepared. There is no reference to fate, a single mistake, or roots. This confirms that option (a) is the correct explanation of the idiom.

Why Other Options Are Wrong:
Option (b) talks about deciding one's fate, which may involve planning but does not match the specific idiom back to the drawing board.
Option (c) mentions wasted efforts due to one mistake, but it misses the key idea of starting afresh with a new plan.
Option (d) focuses on returning to roots or origins, which is a different metaphor and not linked to drawing boards or planning.

Common Pitfalls:
Many candidates over focus on the idea of failure and choose options that mention wasted effort without checking whether the idea of starting again is included. Others may confuse this idiom with expressions about destiny or returning home. To avoid such mistakes, always ask yourself what people actually do in real situations when they say back to the drawing board: they begin planning again after a failure.

Final Answer:
The idiom back to the drawing board means that a plan has failed and a new one must be created, so the correct option is An idea has been unsuccessful and that a new one must be devised.