In the 1600s, it might take several months for a letter to get from the “New World" (the Americas) to
Europe. Now we can video conference with people around the world instantly. This is one example
of what Human Geography concept?

Communications geography

Explanation:

This is an example of the field of communications geography. This is a nascent field that is considered a subdiscipline of human geography. Communications technology explores the connection between human interactions with space and time and the adoption of increasingly complex information and communication technologies (ICTs). This area would be the one most likely to study the differences between communication in the late 1600s and communication in the present.

see below  

explanation:

all of the above