What Does "Course of Dealing" Refer to When Interpreting the Express

Multiple Choice

What does "course of dealing" refer to when interpreting the express terms of a written statement?

A) the previous conduct of the parties regarding the contract in question
B) the conduct of the parties in prior transactions and contracts
C) the conduct of contractual parties with parties not involved in the contract
D) any practice of dealing that is regularly observed or adhered to in an industry