What is the difference between classification and regression in machine learning?

Correct answer: Classification predicts categories while regression predicts continuous numerical values

Option C is correct because classification algorithms predict which discrete category or class a data point belongs to (for example, spam or not spam, cat or dog), while regression algorithms predict a continuous numerical output (for example, house price, temperature, or sales volume). Option A is incorrect because speed depends on the algorithm implementation, dataset size, and hardware, not on whether the task is classification or regression. Option B is incorrect because data requirements depend on the complexity of the problem and the model architecture, not on the task type; regression problems can require less data than complex multi-class classification problems. Option D is incorrect because regression applies broadly to any continuous prediction problem, including cross-sectional data, and is not limited to time-series data.