She is as sweet as pie.
a. personification
b. simile
c. hyperbole
d. metaphor

Well, lets see. 
Personification is giving human-like qualities to something not alive.  The sentence is not doing this, so it cannot be personification. 
A hyperbole is an extreme exaggeration. Is this sentence displaying an example of extreme exaggeration? No, so it cannot be this.
A metaphor is a comparison of one thing to another NOT using like, than, or as. This sentence is a comparison, but it contains the word "as," so it cannot be metaphor.
The only choice left is SIMILE (in case you just want the answer  ) because it is a comparison using the word as. Hope this helped! 

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