What was one effect of European influence on Southeast Asia?

New roads and railroads were constructed.

Rulers built palaces in the European architectural style.

The Vietnamese absorbed much of the European culture.

The Islamic religion spread throughout the region.

The correct answer is - New roads and railroads were constructed.

Even though European colonization of Southeast Asia was not as planed and did not had the wanted effects, the European colonizers did made a basic infrastructure of roads and railroads that they used for easier communication, traveling and trade, but after the European colonizers left this infrastructure left behind and free for use from the people of Southeast Asia.