How many people averaged fewer than 4,000 steps each day?

7

10

19

21

The question cannot be answered without further information.

To find the number of people who averaged fewer than 4,000 steps each day, we need to add up the number of people from each of the given options.

7 + 10 + 19 + 21 = 57

Therefore, there were 57 people who averaged fewer than 4,000 steps each day.