Table $25-2$

$\backslash$table$[[$Days of Labor,Units of Output$],[0,0],[1,10],[2,18],[3,25],[4,30],[5,33],[6,34]]$

Refer to Table $25-2.$ Suppose that the firm pays its workers $$75$ per day. Each unit of output sells for $$10.$ How many days of labor should the firm hire?

$$ a$.1$

$$ b$.2$

$$ c$.3$

$$ d$.4$