:in federalist no. 51, james madison's concerns about a powerful legislative branch point to his belief in a) federalism b) bicameralism c) direct democracy d) individual rights

Answer; 
Bicameralism 
In Federalist No. 51, James Madison's concerns about a powerful legislative branch point to his belief in Bicameralism. 

Explanation; 
Madison's response to those who feared a too-powerful legislative branch of government was Bicameralism. Literally it means "two houses," but practically it meant splitting the legislative branch into the House of Representatives and the Senate.