FF thE mArginAl BEnEFit oF thE lAst unit oF A gooD or sErviCE ConsumED wAs $25, thE mArginAl BEnEFit oF thE nExt unit ConsumED is most likEly to BE:
A．

A. $25.

B．

B. $24.

C．

C. $26.