Please provide very brief $($clear and concise$)$ responses to each question. Cite any sources in APA format and list them in a reference list at the end of the document.; however, you do not need to adhere to any other APA guidelines.

$1.$ Classify the following descriptions of constraints as bounds, limitations$,$ requirements, proportional relationships, or balance constraints:

a$.$ Each serving of chili should contain a quarter$-$pound of beef.

b$.$ Customer demand for a cereal is not expected to exceed $800$ boxes during the next month.

c$.$ The amount of cash available to invest in March is equal to the accounts receivable in February plus investment yields due on February $28.$

d$.$ A can of premium nuts should have at least twice as many cashews as peanuts.

e$.$ A warehouse has $3,500$ units available to ship to customers.

f$.$ A call center needs at least $15$ service representatives on Monday morning.

g$.$ An ice cream manufacturer has $40$ dozen fresh eggs at the start of the production shift.

$2.$ Explain how to graphically visualize linear optimization models with two variables.

$3.$ How can you conduct what$-$if analyses for integer optimization models?

$4.$ What should you look for in models to ensure that sensitivity information is interpreted correctly?