How does the lossy file format reduce the file size?

a.) by using a binary system
b.) by converting the format
c.) by reducing the pixels
d.) by using an algorithm
e.) by cropping the image

What is it called during the editing process when the processor ensures that a character holding a coffee mug from one angle is holding the same mug in the same way when the shot switches to another camera at another angle? cinematography continuity technology prop use