Liliana wants to start a seventh-grade computer club at Hamden Middle School. She surveyed 20 seventh-grade students at the town park. She asked each student how many hours they spend on their computers each week and obtained the following results:

[tex]\[8, 15, 0, 11, 12, 13, 16, 13, 0, 4, 17, 14, 30, 13, 5, 12, 1, 13, 12, 21\][/tex]

What is the ratio of the total number of students who used their computers to the total number of students surveyed?

A. [tex]$\frac{2}{20}$[/tex] or [tex]$\frac{1}{10}$[/tex]

B. [tex]$\frac{2}{18}$[/tex] or [tex]$\frac{1}{9}$[/tex]

C. [tex]$\frac{18}{20}$[/tex] or [tex]$\frac{9}{10}$[/tex]

D. [tex]$\frac{18}{2}$[/tex] or [tex]$\frac{8}{1}$[/tex]

First, note that Liliana surveyed a total of [tex]$20$[/tex] seventh-grade students.

Next, we determine the number of students who used their computers. Since a student is considered to have used a computer if they spent more than [tex]$0$[/tex] hours, we count all the students whose reported hours are greater than [tex]$0$[/tex]. Out of the [tex]$20$[/tex] data values, only [tex]$2$[/tex] of them are [tex]$0$[/tex]. This means the number of students who used their computers is

[tex]$$
20 - 2 = 18.
$$[/tex]

Now, the ratio of the number of students who used their computers to the total number of students is

[tex]$$
\frac{18}{20}.
$$[/tex]

To simplify this fraction, divide both the numerator and the denominator by their greatest common divisor, which is [tex]$2$[/tex]:

[tex]$$
\frac{18 \div 2}{20 \div 2} = \frac{9}{10}.
$$[/tex]

Therefore, the ratio is

[tex]$$
\boxed{\frac{9}{10}}.
$$[/tex]