$\backslash$table$[[$Basic$,Z,x1,x2,x3,x4,$S$1,$S$2,$S$3,$RHS$],[$Z$,1,0,-10,-1,0,0,0,2,20],[$S$1,0,0,2\mathrm{.}5,1\mathrm{.}75,4\mathrm{.}25,1,0,-0\mathrm{.}25,37],[$S$2,0,0,0,0\mathrm{.}5,2\mathrm{.}5,0,1,-0\mathrm{.}5,3],[$X$1,0,1,-0\mathrm{.}5,0\mathrm{.}25,-0\mathrm{.}25,0,0,0\mathrm{.}25,2\mathrm{.}5]]$

What is the value of $x1?$

a$.2\mathrm{.}5$

b$.1$

c$.3$

d$.37$

e$.0$

f$.20$