What is the correct method for constructing a pair in Scheme?

What is the correct method for constructing a pair in Scheme?

What is the correct method for constructing a pair in Scheme? 

 
    Answers:

    A. (append 1 2)
   
    B. (1 . 2)
   
    C. (combine 1 2)
   
    D. (cons 1 2)

Answer. D.