At 28 February 20X1, a company's provision for doubtful debts amounted to 24,000. In the year to 28 February 20X2 it decided to increase the provision for doubtful debts at 24,600. What is the change to the income statement for the year ended 28 February 20X2 in relation to bad debt expense?

a) 24,600 decrease b) 600 decrease c) 24,600 increase d) 600 increase