The cost of a snowboard is $$579\mathrm{.}99.$ The required expenses are $5\%$ of the cost and operating profit is $20\%$ of the cost. Show your work. Round your final answers to $2$ decimals.

a$)$ What is the regular selling price? $(2$ marks$)$

b$)$ What is the break$-$even price? $(1$ mark$)$

c$)$ During a spring promotion, the seling price was reduced by $$25.$ What is the profit or loss at the sale price? $(1$ mark$)$