The answer is A. Multitasking. For three reasons: You’re less productive. It is scientifically proven that there is no such thing as multitasking. You're simply switching from one task to another. When your brain tries to switch it needs to rethink about what its doing which wastes time. You sabotage your ability to do good work. Constantly switching from one thing to another means you can't focus on one specific thing. This often leads to mistakes which means you need to take extra time to fix it anyway. You squelch your creative juices. In other words when you go back and forth from one thing to another you're preventing your thoughts from developing into other thoughts. Which could potentially prevent a brilliant idea.Stay safe. Focus!