When is the balance of tax due for each of the following entities?

$($a$)$ a public corporation, resident in Canada

$($b$)$ a Canadian$-$controlled private corporation, with taxable income less than $$500,000,$ and claiming the small business deduction

$($c$)$ an individual who carried on business in the year

$($d$)$ an individual where no business is carried on by the individual or their spouse