Step 1: Analyzing the options.
The sentence is about the effects of premature greying on the workforce.
- (C) starts by describing the impact: "has a negative effect."
- (B) follows by specifying the affected area: "long term economic growth."
- (D) explains a broader consequence: "required for large economies."
- (A) completes the effect: "on productivity an(D)"
Step 2: Conclusion.
The correct order is: "Premature greying of the workforce has a negative effect on long term economic growth, required for large economies, on productivity an(D)"
Thus, the correct answer is 3. (C), (B), (D), (A).
Final Answer:
\[
\boxed{\text{The correct answer is 3. (C), (B), (D), (A).}}
\]