What is a valid keystroke usage when working with an existing PCF file? 1) Use ALT + SHIFT + E from the browser to start Studio if it is not already running and open the PCF that was used to render the page. 2) Use ALT + SHIFT + W from the browser to open the PCF in Studio. 3) Use ALT + SHIFT + I from the browser to see the list of PCFs used to render the page. 4) Use ALT + SHIFT + L from Studio to reload changes to PCFs..