Primo Pies is a chain of pizza restaurants. A data analysis is required to determine why operating income has been decreasing given that revenue has been steady. What descriptive questions can be asked in this data analysis?

Group of answer choices

a$.$ Is there a correlation between increases in marketing expense and increased revenue?

b$.$ How would increasing menu prices by $10\%$ affect operating income?

c$.$ Has there been an increase in employee compensation which has increased operating expenses?

d$.$ How would closing down a restaurant with low operating income affect the company's overall performance?