Time management is the ability to plan and control how you spend the hours of your day well and do all that you want to do.
Source: Chapter 2, Session 5: Self-regulation — Time Management
This is a direct definition from the textbook. For a 1-mark question, one precise sentence is sufficient. Examiners look for the key phrases: plan, control, and hours of the day. Do not add examples or extra points — that wastes time and earns no extra marks.