Ngành kinh tế nào sau đây phát triển mạnh dưới thời kỳ nhà nước Chăm pa A. chế tạo máy B. Đóng tàu biển C. Khai thác lâm sản D. Chế tạo vũ khí

The main economic activity of the Champa people was agriculture, specifically rice cultivation in various types of fields such as lowland, upland, and saline fields. They also engaged in the production of valuable minerals like gold, silver, and agarwood, as well as precious forest products such as ivory, rhinoceros horns, and most notably, agarwood. Additionally, a significant portion of the population made a living through fishing and trading with foreign ships. The Champa society had various social classes, ranging from the nobility to commoners.

Based on this information, the economic activity that developed strongly during the Champa period was C. khai thác lâm sản (exploitation of forest products).