Which one of the following statements is correct $?$a$)$ If Sally and her husband file jointly then Sally can never be

claimed as a dependent by her parents $.$b$)$ If Sally and her husband have no taxable income but file a

joint return because they are due a refund $,$ Sally cannot be

claimed a dependent by her parents $.$c$)$ If Sally and her husband have children $,$ Sally can still be

claimed as a dependent by her parents if Sally and her husband so

not file a joint return $.$d$)$ If Sally is under the age of $24$ and a full time student then

her material status is irrelevant in determining if her parents can

claim her as a dependent $.$