This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Which of the following are formal thought disorders?a) Thought broadcastb) Circumstantiality c) Loosening of associationd) Delusion 
Select and explain. 
A. c, B. bd, C. ab, D. ac
B: bd
Answer: B: bd 
Explanation: None