Step 1: Understanding the concept of training. 
  
Training typically focuses on imparting skills and knowledge that employees can apply in their day-to-day work. Practical knowledge, which is directly related to the work environment, is the primary focus of training programs. 
Step 2: Analyzing the options. 
  
(A) Theoretical knowledge: Incorrect. While theoretical knowledge is important, training focuses more on practical application rather than abstract theories. 
  
(B) All-round knowledge: Incorrect. Although all-round knowledge is important, the emphasis in training is on practical knowledge. 
  
(C) General knowledge: Incorrect. General knowledge is important for overall development but is not the main focus of training. 
  
(D) Practical knowledge: Correct. Training emphasizes practical knowledge, which employees can apply directly in their work tasks. 
Step 3: Conclusion. 
  
The correct answer is (D) Practical knowledge, as training primarily focuses on enhancing practical skills.