Data Validation in wordpress

In my theme, i am grabbing user input with get_option() and according to that input i want to i want to declare a new variable and print in my single.php file. For example:

now when i echo $second_col_class variable in my php files it works fine. But when i run themecheck plugin it shows an error like this.

“Possible data validation issues found. All dynamic data must be correctly escaped for the context where it is rendered.”

i want to echo that variable like below.

I cannot use isset() function because it just returning true or false. Is there any alternative to this?