During $"$No Hands Across America," a car was driven by a computer program from Pennsylvania to California. How did the program work?

a$.$ It used a neural network to control the throttle and brake of the car.

b$.$ It used a neural network to control the angle of the steering wheel

c$.$ It was guided by a series of sensors placed along the roadway beforehand.

d$.$ Scientists were "driving" it remotely from a laboratory.