Duffy Associates is a partnership engaged in real estate development. Olinto, a civil engineer, billed Duffy $$40,000$ in the current year for consulting services rendered. In full settlement of this invoice, Olinto accepted $$15,000$ cash payment plus the following.

Fair Market Value Carrying Amount on Duffy's Books

$10\%$ partnership interest in Duffy $$10,000$ N$/$A

Automobile $7,000$ $$3,000$

What amount should Olinto, a cash basis taxpayer, report in his current$-$year return as income for the services rendered to Duffy?

a$.$ $$15,000$

b$.$ $$28,000$

c$.$ $$32,000$

d$.$ $$40,000$