In order to reduce the average cost, when Ford Motor plans its production of cars and trucks for $2019$ it reaches out to key suppliers who produce component parts in Mexico $($tires$,$ batteries, windshields, seats, etc.$).$ Further, in order to secure an advantageous price, they issue orders in the millions of units. This process is called?

a$.$

Scientific management

b$.$

systems theory

c$.$

economies of scale

d$.$

quantitative management