$1.$ Let M be the number of units to make and B be the number of units to buy. We want to minimize the total cost. If it costs $ $2$ to make a unit and $ $3$ to buy a unit and totally exactly $4000$ units are needed, the constraint that totally $4000$ units are needed can be formulated as a$.$ M$+$B$>=4000$ b$.$ M$+$B$=4000$ c$.2$ M$+3$B$=4000$ d$.2$ M$+3$ B $<=40002.$ Use the information given in #$1.$ The objective function is a$.$ Max $2$ M$+3$B b$.$ Min $4000($M$+$B$)$ c$.2$ M$+3$B d$.$ Min $2$ M$+3$B $3.$ A company makes two products, A and B$.$ A sells for $ $100$ and B sells for $ $90.$ The variable production costs are $ $30$ per unit for A and $ $25$ for B$.$ To maximize the total profits, the company's objective function could be written as a$.100$A$+90$B b$.$ Max $30$A$+25$B c$.$ Max $70$A$+25$B d$.$ Max $70$A$+65$B $4.$ Let A$,$ B$,$ and C be the amounts invested in companies A$,$ B$,$ and C$.$ If no more than $60\%$ of the total investment can be invested in company C$,$ then a$.$ C $<=0\mathrm{.}6$ b$.-0\mathrm{.}4$A$+0\mathrm{.}6$B$-0\mathrm{.}4$ C$>=0$ c$.-0\mathrm{.}6$A$-0\mathrm{.}6$B$+\mathrm{.}4$ C$<=0$ d$.-0\mathrm{.}4$A$+0\mathrm{.}6$B$-0\mathrm{.}4$ C$<=05.$ is the process of translating a verbal statement of a problem into a mathematical statement. a$.$ Simulation b$.$ Problem description c$.$ Problem formulation d$.$ Linear programming