When you are driving, a. it is okay to rest your left elbow on the open window, as long as your left hand is still on the steering wheel. b. it is okay to rest your left arm on the open window and drive with only your right hand on the steering wheel. c. you should not rest your left elbow on the open window?

c.you should not rest your left elbow on the open window?

you're not in complete control of the heavy, fast moving thing = the car

c.you should not rest your left elbow on the open window?

While riding in an automobile vehicle certain rules and regulations need to be followed to ride safely. Among the given options, c.you should not rest your left elbow on the open window? is the most relevant one because if you place your arm on the window there are changes that it could be hit by other riding vehicle. So, as a safety precaution the arm should not rest on window on driving.  

d) physical means can be used to separate the components of air.

the answer is a. hope this .