Is it permitted to take one hand off the wheel or handlebar while driving?

1. Yes, only for tuning the vehicle’s radio or operating the lighter
2. Correct answer: No, except for changing gears and operating the direction indicator, or in order to assure the vehicle's proper function.
3. Not for any reason
4. Yes, for using a cellular phone

WhyYou may take one hand off the wheel only for what driving requires: changing gear, the indicator and so on. Phone and radio don't count. 'Always forbidden' is wrong too, or you couldn't even signal.