Cullumber Company has identified that the cost of a new manufacturing equipment will be $28000, but with the use of the new equipment, net income will increase by $3000 a year. If depreciation expense is $1000 a year, the cash payback period is:

a. 14.0 years.

b. 28.0 years.

c. 7.0 years.

d. 9.3 years.