Tron, Inc has a times interest earned ratio of $4\mathrm{.}1.$ Based on this ratio, a creditor knows that Tron's EBIT must decline by more than $\_\_\_\_\_\_\_$ percent before Tron will be unable to cover its interest expense. a$)33\%$ b$)40\%$ c$)67\%$ d$)75\%$ e$)80\%$