Option (क) रॉकेट is the correct answer. The textbook context clearly establishes this through multiple references. The teacher in the text explains that 'वैज्ञानिकों ने चाँद पर एक रॉकेट भेजा' (scientists sent a rocket to the moon). When asked how one goes to the moon, students respond 'रॉकेट से' (by rocket). The text further confirms that rockets like Chandrayaan-1, 2, and 3 have successfully gone to the moon. A bus (बस) is a road vehicle and an airplane (हवाई जहाज) cannot travel to the moon as it requires air to fly, whereas there is no air in space between Earth and the moon.