The mauryan empire grew as a result of

a. the collapse of the harappa civilization
b. forming a partnership with alexander the great
c. buddhist monks spreading their religion to new places
d. it’s leaders conquering small kingdoms across india

The answer is  D. It’s leaders conquering small kingdoms across India.

Explanation:

The Mauryan Empire (321 BCE - 185 BCE) was a powerful political unit emerged after the death of Alexander the Great. Its founder was Chandragupta Maurya. It was higly centralized and it boasted an efficient civil service and a good army. One of its greatest rulers, Asoka, converted into Buddhism and made an important contribution to spreading this doctrine in India.

Answer:

The Mauryan Empire grew as a result of D. It’s leaders conquering small kingdoms across India

Explanation:

"Chandragupta Maurya" was the founder of Mauryan empire. He defeated Nanda dynasty and came to power.  

Mauryan had a strong army and also an excellent spy system to make sure of their internal and external securities. They were known for their big economic accomplishment in the country.

Chandragupta conquered most of the northern parts of India and formed a united northern India. They became wealthy through trade. He also set up postal system. Gradually, conquering most of the small kingdoms across India, they became the first largest empire in India.

the answer is option a.