Help me with these 3 questions, thank you

1. Below is the result of operations of Empresas ABC for the month of July:

Sales (2,500 units) $7,500

Variable costs (3,250)

Fixed costs (4,000)

Net income $250

What is the effect on net income if ABC sells an additional 500 units per month?

a. Increase by $650

b. Increase by $1,500

c. Increase by $850

d. Increase by $500

2. ABC wants monthly ending inventory to equal 30% of projected sales for the current (current) month. The sales projection for February is $90,000. Ending inventory for the month of January was $24,000. Based on this information, the projected purchases for February will be:

a. $63,000

b. $93,000

c. $66,000

d. $87,000

3. Which of the following costs is normally considered a fixed cost?

a. cost of goods sold

b. Hourly wages for assembly employees

c. Direct materials (raw material)

d. executive salary