The punctuation is correct if that is how how the statement started and ended.
Even though I've always been food at math, it's not my favorite subject.
C.
Complete Sentence
I dropped my phone three times on my into the building, it didn't break.
B.
Run-On
Andrea's brother has two children, her sister has four children.
C.
Complete Sentence
I am almost finished with college, my dream is to open my own business.
B.
Comma Splice
Alisha passed her licensing exam last week.
C.
Complete Sentences
Answer:
Twain is satirizing society’s greed by having Huck’s father return under the pretense of caring for Huck when all he really wants is money.