How is the truman doctrine related to this question from the telograph?

Economic assistance to the countries that needed it:

To contain communism, Truman promised to give financial aid to countries like Turkey.

- encouraging nationalism

- returning to conservative political policies

a historian researching the immigration policies of the early 1900s would expect a source written today,rather than in 1910 to :

( a ) be more interested in objective data and statistics.