Which tactic of the civil rights movement was most successful in gaining public support for the twenty-fourth amendment ?
a) supporting african american candidates for election .
b) advocating poll taxes
c) holding nonviolent sit-ins
d) recruiting the support of sympathetic white legislators

The correct answer is C.

The 24th Amendment to the US Constitution was ratified in 1964 and it banned the usage of poll taxes in Southern States, as these were discriminatory and prevented the most humble sectors of the population and minorities (black citizens) from voting.

As most of the actions undertaken during the Civil Rights Movement, public support was gained by non-violent methods, such as sit-ins.

c) troops march forward in close formation against newer, more accurate weapons