Read the passage carefully and answer the questions that follow.
By 1910, the motor car was plainly conquering the highway. The private car was now part of every rich man’s establishment, although its price made it as yet an impossible luxury for most of the middle class. But for the adventuresome youth, there was the motorcycle, a fearsome invention producing accidents and ear-splitting noises.
Already, the dignified carriages and smart pony-traps were beginning to disappear from the roads, and coachmen and grooms, unless mechanically minded, were finding it more difficult to make a living.
The roads, which had gone to sleep since the coming of the railway, now awoke to feverish activity. Cars and motor cycles dashed along them at speeds which rivalled those of the express trains, and the lorry began to appear.
Therefore, the road system was compelled to adapt itself to a volume and speed of traffic for which it had ever been intended. Its complete adaptation was impossible, but the surface was easily transformed and, during the early years of the century, the dustiness and greasiness of the highways were lessened by tar spraying. To widen and straighten the roads and get rid of blind corners and every steep gradient were tasks which had scarcely been tackled before 1914.
The situation was worst of all in towns where not only was any frequently increased by the short-sighted eagerness of town authorities in laying down tramlines.
Yet it was not only the road system that was in need of readjustment; the nervous of those who used and dwelt by the road suffered. The noises caused by the conversion of the roads into speedways called for a corresponding tightening up of the nerves; and especially in the towns, the pedestrian who wished to preserve life and limb was compelled to keep his attention continually on the stretch, to practice himself in estimates of the speed of approaching vehicles and to run or jump for his life ventured off the pavement.
The writer uses the expression unless mechanically minded to refer to
A. coachmen and grooms adaptable to the new technology B. coachmen grooms who chose to become mechanics C. town authorities laying down tramlines D. those amenable to change and development
