What is the difference, in seconds, between the current timestamp in the GMT time zone and the current timestamp in your local time zone?

You must make a call to ................... to specify what time zone you want calculations to take place in before calling any date functions.

What would happen if the following script were run on a Windows server set to Moscow, Russia’s time zone?
echo gmmktime(0, 0, 0, 1, 1, 1970);