From Twitter:
Choose:

Mom always __ for Christmas Day by __ many gifts and lots of food. Yes, she is always well-__ for that most special of days. And--we always have a wonderful time.

a. prepared
b. prepares
c. preparing

The Answers Are: prepares (a), preparing (c), prepared (a)

Explanation:
After 'always', a simple tense verb, we can have a past tense or a present tense verb. If we look at the end of the sentence, we see 'we always have a wonderful time', meaning this is the present, not the past--so we need a present tense verb after always--so the answer to the first option is 'prepares'.

After 'by' we need a gerund, because by introduces nouns of process or conveyance and actual things; think of how we say 'go by train', 'solve the problem by using calculus', the cat reached the window by jumping.

After 'is always' we need an adjective form or a continuous verb form, because 'is', a linking verb, and 'always' as an adverb require a description or a habitual action, but the choices offer only one 'ing' option and it is needed elsewhere!