Answer:
C. Father and his 35-year-old son investing in separate account.
Explanation:
Quantity discount when offered relates to one particular account, and not multiple accounts at a time.
In a transaction joint accounts are called as single person where there is only one main account in consideration and no secondary account exists for the same.
As in the given options,
Option A of husband and wife investing in a joint account means a single account is made of which both the husband and wife are controllers.
Option B is of UTMA account which is made for the benefit of the minor child, although involves two people that is parent and child, but is run individually by the parent and is a single account.
Further Option C provides for separate investment accounts , which means two different accounts and therefore are completely different one of father and another of son, thus do not qualify of quantity discount jointly, either of the one account can claim the quantity discount as a person.