How did technological innovations, such as improved roads, affect western migration?

Improvised roads and routes mean that the travel between two countries. The migration becomes easy. The trade becomes more convenient and cheaper as compared to earlier times due to less travel cost.

Tourism has increased due to convenient travel routes. Technological developments has increased trade opportunities and the connection between the countries has become stronger and more efficient.

I hope the answer is helpful.

Thanks for asking.

b) to encourage free trade

the answer is either c or d i think its d