If you work hard, you ____ good marks.

The sentence “If you work hard, you ____ good marks” uses the first conditional (“will get”) to express a likely future outcome based on a condition. In English, the first conditional (if + present simple, will + base verb) indicates a real possibility. Hard work is likely to result in good marks. Options A (present, habitual), C (past), and D (present perfect) do not fit the future-oriented conditional structure, making B the correct answer.