What was the war strategy that the Johnson administration pursued in Vietnam? a. gradually withdrawing U. S. troops and turning the war over to South Vietnamese troops

b. using air power to destroy Vietcong guerrilla strongholds in South Vietnam, while simultaneously launching a ground offensive against North Vietnam

c. keeping Vietnam divided, with a Communist government in the north and a pro-Western government in the south

d. fighting a war of attrition on the premise that continuous use of heavy artillery and air power would eventually exhaust North Vietnam's resources