In UiPath Studio, you can use DateTime and TimeSpan variables to store and manipulate date and time values. A DateTime variable represents a specific point in time, such as the current date and time, or a date in the past or future. A TimeSpan variable represents a time interval, such as one hour, two days, or three weeks.

To show what hour was 12 hours prior to the date from the variable, you can use the AddHours method on the DateTime variable and pass a negative value. For example, if you have a DateTime variable called CurrentDate that stores a date and time value, you can write:

CurrentDate.AddHours(-12).Hour

This expression returns an integer value that is the hour component of the DateTime value that is 12 hours before the CurrentDate value. For example, if CurrentDate is 2024-02-08 10:51:49, then the expression returns 22.

The other options are not correct expressions for showing what hour was 12 hours prior to the date from the variable. Option A is invalid, because the DateTime class does not have an AddHours method. Option C is incorrect, because the DateTime variable does not have a SubtractHours method. Option D is incorrect, because the DateTime class does not have a SubtractHours method.