A part $1^{\text{'}\text{'}}$ thick has a tapped hole called out as #$10-32$ UNF$-2$B $\mathrm{.}50DP,$ tap drill thru allowed. Which of the following sequences is correct?

A$.$ Tap drill using a #$21$ drill to $\mathrm{.}50$ deep, tap.

B$.$ Center drill, tap drill using a #$21$ drill $\mathrm{.}50$ deep, and tap $\mathrm{.}50$ deep.

C$.$ Center drill, tap drill using a #$21$ drill $.32$ deep, and tap as deep as possible with a standard tap.

D$.$ Center drill, tap drill using a #$21$ drill $\mathrm{.}66$ deep to thru, and tap $\mathrm{.}50$ deep.