The correct answer is C. Harshavardhana.
Harshavardhana (590-647 CE) was an Indian emperor who ruled over the northern Indian subcontinent from 606 to 647 CE. He was the founder of the Harsha Empire, which at its peak included much of the Indian subcontinent north of the Narmada River. Harsha was a powerful and successful ruler, and he is also remembered for his patronage of the arts and literature.
The other options are incorrect. Chandragupta I was the founder of the Gupta Empire, which ruled over much of northern India from the 4th to the 6th centuries CE. Samundragupta was the grandson of Chandragupta I and the third emperor of the Gupta Empire. Ashoka was the third emperor of the Mauryan Empire, which ruled over much of the Indian subcontinent from the 3rd to the 2nd centuries BCE.
Chandragupta I was a powerful and successful ruler, and he is also remembered for his patronage of the arts and literature. Samundragupta was a powerful and successful ruler, and he is also remembered for his military conquests. Ashoka was a powerful and successful ruler, and he is also remembered for his Buddhist reforms.
However, none of these rulers was known as Siladitya. The name Siladitya is a Sanskrit name that means “the sun of the moon.” It is a title that was given to Harshavardhana by his subjects.