If a Canadian public corporation is experiencing a year-to-year decrease in income tax, the most advantageous calculation of instalments that would be allowed is: a. monthly, based on the estimated income tax for the current year. b. quarterly, based on the estimated income tax for the first preceding year. c. monthly, based on the estimated income tax for the first preceding year. d. quarterly, based on the estimated income tax for the second preceding year and the immediately preceding year. e. monthly, based on the estimated income tax for the second preceding year and the immediately preceding year. f. quarterly, based on the estimated income tax for the current year