Which of the following statements relating to the standard deduction is correct?

a$.$ If a taxpayer is claimed as a dependent of another, the additional standard deduction is allowed in full $($i$.$e$.,$ no adjustment is necessary$).$

b$.$ If spouses file separate returns, both must claim the standard deduction $($rather than itemize their deductions from AGI$).$

c$.$ If a taxpayer dies during the year, the standard deduction must be prorated.

d$.$ If a taxpayer is claimed as a dependent of another, no basic standard deduction is