Concept:Commerce is supported by aids to trade, and transport infrastructure like roads helps goods and services move easily.
Explanation:Good road networks improve connectivity between producers, traders, and consumers.
This reduces transportation time and cost.
It enables businesses to distribute goods to wider markets.
It helps people access goods, services, and employment opportunities.
Therefore, improving road network directly facilitates commerce.
The other options are not trading or commercial activities.
Answer:D. improving road network