At which value total costs of processes X and Y will be equal?

Question

Process X has a fixed cost of Rs 40,000 per month and a variable cost of Rs 9 per unit. Process Y has a fixed cost of Rs 16,000 per month and a variable cost of Rs 24 per unit. At which value total costs of processes X and Y will be equal?             

(a) 800                                   (b) 1200

(c) 1600                                   (d) 2000