After$-$tax return is equivalent to:

Question $18$ options:

a$)$

Pretax return $/(1-$marginal tax bracket$).$

b$)$

Pretax return $*(1+$ marginal tax bracket$).$

c$)$

Pretax return $/(1+$ marginal tax bracket$).$

d$)$

Pretax return $*(1-$marginal tax bracket$).$

e$)$

None of the above.