To create a canvas app that uses a responsive design in Power Apps, you should perform the following actions:
B: Configure the height and width properties by using a formula: By using a formula to set the height and width properties, you can ensure that the app will respond to changes in screen size and orientation. For example, you can use the Width() and Height() functions to set the width and height properties based on the size of the screen.
C: Disable the Scale to fit setting: The Scale to fit setting, when enabled, makes the app's content fit on the screen by scaling it down. To create a responsive app, this setting must be disabled.
Reference:
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/responsive-design
https://docs.microsoft.com/en-us/powerapps/maker/canvas-apps/functions/function-width