Select the best option to complete the confused roommate's question.

Why are your clothes covered in mud? _____ in the garden again?

The correct answer is Have you been digging.

We use the Present Perfect Continuous for an action that has recently stopped and has a visible, present side effect or result (like being covered in mud, sweating, or being out of breath). The focus is on the messy activity itself, not on the finished result of the digging.