when the president recognizes a nation, he usually

a. sends the nationa diplomatic representative
b. declares the nation persona non grata
c. declares war on the nation
d. registers strong disapproval of the nation's government
a.

Absolutely!

Which is a technology that has helped to change the modern presidency?

sends the national diplomatic representative

When the president recognizes a nation, he usually sends a diplomatic representative to establish official diplomatic relations with that nation. The process of recognizing a nation involves the president acknowledging the existence and sovereignty of the nation, and establishing the basis for formal diplomatic engagement.

To arrive at the correct answer, you can eliminate options b, c, and d since they are not directly related to the act of recognizing a nation. The most appropriate option is a, which describes the president sending a diplomatic representative to establish formal relations with the nation.