What is the design specification when the technician cost is approximately $$15?$

a$.(1\mathrm{.}825,1\mathrm{.}925)$

b$.(1\mathrm{.}786,1\mathrm{.}964)$

c$.(1\mathrm{.}745,2\mathrm{.}005)$

d$.(1\mathrm{.}834,1\mathrm{.}916)$