Which statement(s) is(are) true? (Note: If two or more statements are true, and you select only one true statement, you will not get partial credit for the partially correct selection).Group of answer choicesa. Services make up a small percentage of todays U.S. economy.b. The Clark-Fisher hypothesis implies that as productivity increases in one sector, the labor force moves to another sector.c. Technological advances (modernization) and better (smarter) processes facilitated increased productivity in the manufacturing sector.d. b and c are true.