Which of the following statements about mobile device usage is true?

a$.$

Mobile users are less likely to view video ads than are desktop or laptop users.

b$.$

The fastest growth among U$.$S$.-$based mobile users is occurring in cities.

c$.$

Most mobile users spend more than $16$ hours per day using their devices.

d$.$

The majority of mobile device usage minutes are spent inside the user$$s home.