A small police department wants to buy a machine that performs alcohol breath tests. It has never had this capability before but feels it is an essential tool as the community grows. The machine costs about $$5000,$ which is almost $75\%$ of the department's entire supply budget. This purchase is an example of which type of buying situation?

a$.$ extensive buying

b$.$ modified rebuy

c$.$ new task buy

d$.$ straight rebuy