Intuit Inc. develops and sells software products for the personal finance market, including popular titles such as Quickbooks and TurboTax. Classify each of the following cost and expenses for the company as with variable to the number of units produced and sold:

a. Packaging costs

b. Sales commissions

c. Property taxes on general offices

d. Shipping expenses

e. Straight-line depreciation of computer equipment

f. President's salary

g. Salaries of software developers

h. Salaries of human resources personnel

i. Wages of telephone order assistants

j. CDs

k. Users' guides