Step 1: Understanding communication types. 
  
Communication in an organization can be categorized into different types: written, verbal, and formal. These types are used in various situations depending on the needs of the organization and the nature of the information being conveyed. 
Step 2: Analyzing the options. 
  
(A) Written: Written communication includes emails, reports, and other documents. It is formal and useful for record-keeping. 
  
(B) Verbal: Verbal communication is spoken communication and can be formal or informal. It is widely used for day-to-day interactions. 
  
(C) Formal: Formal communication includes official memos, reports, and other structured forms of communication. It can be either written or verbal. 
  
(D) All of these: Correct. All the above forms of communication (written, verbal, and formal) are essential and used in various organizational contexts. 
Step 3: Conclusion. 
  
The correct answer is (D) All of these, as all types of communication are used in management.