Here is the passage again:
To make Sylvia, the party's hostess, happy. Kelvin steeled himself, dipped
his spoon into the squid eyeball stew, and began to drain the bowl.
You chose to use Punctuation Rule 6 to fix the problem:
Infinitive phrase + , + main clause.
The correction looks like this:
To make Sylvia, the party's hostess, happy, Kelvin
steeled himself, dipped his spoon into the squid eyeball stew, and began
to drain the bowl.
Well done! You deserve that pizza!