The candle with a 750 mL beaker as the cover would burn longer than the rest.
The burning of the candle requires oxygen and the volume of oxygen each beaker can hold depends on the volume of the beakers.
Thus, a beaker of 750 mL capacity will hold more oxygen than beakers of 250 mL or 150 mL capacity.
Since the higher volume beaker has the capacity to hold more oxygen than the rest, it means that the candle will be able to burn longer in it than the rest.
More on oxygen and burning can be found here: https://brainly.com/question/9641392?referrer=searchResults