For the firm Carrot Brothers with production function q = 0.25kl, c = 0.15 + 0.15k + 0.10l, find the total cost function.

a) 0.25kl + 0.15 + 0.15k + 0.10l
b) 0.25kl - 0.15k - 0.10l
c) 0.25k^2 + 0.15l^2
d) 0.40kl + 0.25k + 0.10l