A home furnishing company that manufactures three types of furniture: tables, chairs, and sofas. The following table gives the necessary quantity of raw materials, the time required for each product from the manual and automatic labor hours, and the profit achieved from producing one unit of each of the three products.

$\backslash$table$[[$Products$,$sofa,chairs,tables,$\backslash$table$[[$Number of$],[$resources$],[$available$]]],[$raw materials,$35,20,25,1200$units$],[$Automatic working hours,$5,6,4,235$hours$],[$Manual work hours,$3,1,2,100$hours$],[$profit$/$unit$,200,100,125,-]]$

The linear programming model for this problem can be formulated as follows:

Max $Z=125x_1+100x_2+200x_3$

Subject $to$:

$25x_1+20x_2+35x_{3}1200$

$4x_1+6x_2+5x_{3}235$

$2x_1+x_2+3x_{3}100$

$x_1,x_2,x_{3}0$

The number of remaining manual labor hours is:

A$.20$ hours

B$.51$ hours

C$.4$ hours

D$.0$ hour