The correct answer is option 4, Vardhamana Mahavira.

Option 1, Ashvaghosa, is not a contemporary of Gautama Buddha. Ashvaghosa was a Buddhist philosopher and poet who lived in the 1st century CE, long after the time of the Buddha.

Option 2, Nagarjuna, is also not a contemporary of Gautama Buddha. Nagarjuna was a Buddhist philosopher who lived in the 2nd century CE, again long after the time of the Buddha.

Option 3, Parsvanath, is incorrect as well. Parsvanath was the 23rd Tirthankara (spiritual teacher) of Jainism, and he predated Gautama Buddha by a few centuries.

Therefore, the correct answer is option 4, Vardhamana Mahavira. Mahavira was the 24th and last Tirthankara of Jainism and lived during the same time as Gautama Buddha, in the 6th century BCE. Both Mahavira and Buddha were contemporaries and influential spiritual leaders in ancient India.