[quote="aurobindomahanty"]
To force a person to retire solely because they have reached a certain arbitrary age is like denying a person a job because of sex, race, or religion.
(A) To force a person to retire solely because they have reached a certain arbitrary age is like denying a person a job
(B) Forcing a person to retire solely because they have reached a certain arbitrary age is like denying a person a job
(C) Forcing people to retire solely because they have reached a certain arbitrary age is like to deny a person a job
(D) Forcing people to retire solely because they have reached a certain arbitrary age is like denying people jobs
(E) To force people to retire solely because they have reached a certain arbitrary age is like denying people jobs
In Options A and B - "THEY" (plural) can't refer to person (singular)- Eliminate
Between C, D, E - sometimes verbs can be used to hold two phrases parallel.
Thus C and E can be eliminated because "forcing" isn't parallel "to deny" (C)
"To force" isn't parallel to "Denying"