An Imperial quart is a British Standards measurement.
Your manual specifies oil capacity in US measure, British Imperial measure, and metric measure.
The stated US quart and Imperial quart listings both equal 1 metric litre.

You would use the 4.8 quart measurement.

 

Thank you.

 

It's the dipstick reading - 10 minutes after shutting off the engine and with the car on level ground - that counts.