Indicate whether the following statements are "True" or "False" regarding the pay$-$as$-$you$-$go feature of the Federal income tax system.

a$.$ Employers have the option of withholding income tax on compensation paid to their employees and to pay this tax to the government.

b$.$ If taxpayers receive income that is not subject to withholding or income from which not enough tax is withheld, they may have to pay estimated tax.

c$.$ The pay$-$as$-$you$-$go feature of the Federal income tax system requires payment of all or part of the taxpayer's income tax liability during the year