Identify the following, a$)$ the objective, b$)$ the variables, c$)$ the objective function, d$)$ the constraints. A company produces three products, A$,$ B$,$ and C$.$ The sales volume for A is at least $50\%$ of the total sales of all three products. However, the company cannot sell more than $80$ units of A per day. The three products use one raw material, of which the maximum daily availability is $240$ lb$.$ The usage rates of the raw material are $2$ lb per unit of A$,4$ lb per unit of B$,$ and $3$ lb per unit of C$.$ The unit prices for A$,$ B$,$ and C are $$20,$ $$50,$ and $$35,$ respectively. How can revenue be maximized?