How can you express the regular activity of going to school using the present continuous tense?

The present continuous tense is used to describe actions that are currently happening or ongoing at the moment of speaking. However, it can also be used to convey actions that are habitual or regular when there is an emphasis on the ongoing nature of the activity. In this case, “I am walking to school every day” suggests that this is an action currently taking place with a certain immediacy, even if it's a regular occurrence.

The other options convey different meanings: using the past continuous in the second choice indicates that the action was ongoing at a specific time in the past but is not currently happening, while the simple present tense in the third choice states a habitual action without the ongoing nuance that the present continuous provides. The last option, using present perfect, refers to a completed action with relevance to the present, which doesn't fit the context of expressing a regular daily activity.

Thus, the correct answer effectively showcases the present continuous tense in a way that emphasizes an ongoing regular activity, aligning with the intent of the question.