Step 1: Understanding scientific management. 
  
Scientific management is a theory of management that analyzes and synthesizes workflows. Its aim is to improve economic efficiency, especially labor productivity. The concept of analyzing work scientifically is highly effective in enhancing productivity. 
Step 2: Analyzing the options. 
  
(A) 25%: This is incorrect; the percentage of analysis in scientific management is much higher. 
  
(B) 30%: This is incorrect. 
  
(C) 50%: While this is closer, the correct answer is higher. 
  
(D) 75%: Correct. 75% of scientific management involves analysis, ensuring work processes are scientifically optimized. 
Step 3: Conclusion. 
  
The correct answer is (D) 75%, as 75% of scientific management focuses on analysis to enhance productivity.