Washington thought that political parties were national unity.

a. to

b. needed for

c. products of

d. destructive to

D. Destructive to national Unity

Explanation:

George Washington (1732-1799) strongly believed and considered that the unity of the nation was the most important; for this reason he thought that the political parties would be harmful and such parties would encourage the division and in consequence the destruction of the United States of America as a democratic republic.

from the conditions of the working class in england by friedrich engels,the main idea is :

yup! you are correct it is b.