Entrepreneurs contribute to a market economy by organizing productive resources in order to

create economic activity

The answer is: Create economic activity

Economic activity refers to the act of creating, delivering, or purchasing goods or services. Creation of economic activity would lead to an increase of number of employment and overall standard of living.

Productive resources in this context refers to labor forces, materials, management skills and the capital. Entrepreneur would utilize all of these things in order to generate revenue that improve the government's budget through taxes.