_____ is the support system on which the efficient working of a modern industrial economy depends.

Infrastructure

The correct answer is Option (3) → Infrastructure

Infrastructure is the support system on which depends the efficient working of a modern industrial economy. Modern agriculture also largely depends on it for speedy and large-scale transport of seeds, pesticides, fertilisers and the produce using modern roadways, railways and shipping facilities. In recent times, agriculture also depends on insurance and banking facilities because of its need to operate on a very large scale.