According to the author, it is a formidable challenge for a computer ______.

A．Take their own bags to the grocery store.
B．Buy things that are overpackaged.
C．Do not buy cloth towels.
D．Do not throw away their cloth napkins.

A．To get anything top of the line.
B．Bikes that are in good condition.
C．To make sure it’s the right height.
D．The most important thing is comfort.