Hello!
The answer is:
B. Exponential growth
Why?
From the statement we know that "It is predicted that for the next 8 years, the number of connected devices in households across the world will be 18.36% more than the previous year."
We know that the expression "will be 18.36% more than the previous year" involves a non-linear growth, since the number of connected devices from a year to another will be related to the previous year, so, we can modelate the situation establishing an exponential growth relationship.
We can calculate the exponential growth using the following equation:

Hence, the answer is:
B. Exponential growth
Have a nice day!