A questionnaire is designed to understand consumer online shopping behaviors in a Midwestern city. Which of the following questions has no obvious violations of the designing rules (covered in the course videos)?

a. How often do you shop online in the last month?

1. Never; 2. 1-3 times; 3. 4-6 times 4. 7 times or more

b. Do you feel online shopping is cheaper and more time-saving than offline?

1. Yes; 2. No; 3. Dont know

c. During March 2018, how much did your household spend on online shopping?

1. Less than $100; 2. $100-499; 3. $500-1000