Based on the borwn v. board of education of topeka supreme court ruling, which of the following actions would be considered unconstitutional?

a. a civil rights activist is jailed for writing pamphlets urging african americans to use nonviolence to resist racism.
b. a veteran of world war ii receives federal aid to attend college and purchase a home in the suburbs.
c. a government official is fired from her job because of her participation in a rally organized by communists.
d. a city government forces african american and white students to attend separate schools.