Which of the following is true regarding the term "capacity to contract"?
a. It refers to the fact that all parties must sign a contract for it to be valid
b. It refers to the fact that contracts must respect certain standards of public order and laws of general protection
c. It refers to the fact that persons who enter contracts must do so freely and without constraint
d. It refers to the fact that contracts must be in writing to be valid
e. It refers to the fact that minors may not, as a rule, enter into contracts unassisted.
