Which of the following terms would likely be considered legal in a written employment contract signed in Alberta?

a$.$ A term preventing an accountant from working for another accounting firm in the province of Alberta for a period of five $(5)$ years.

b$.$ A term providing an employee with no vacation for the first two $(2)$ years of employment.

c$.$ A non$-$disclosure clause preventing an employee from disclosing a special production method of their employer.

d$.$ A term providing an employee with two $(2)$ weeks' worth of notice after working for their employer for $15$ years.