Question

Let's examine _____ for tone and style.
ours
our's

Answer 1

Ours makes more sense.

"Let's examine 'ours' for tone and style"

"Let's examine 'our is' for tone and style"

Answer 2

ours

Step-by-step explanation:

Ours is a possessive pronoun, which is use to replace a noun (not mentioned in the example) and avoid repetition.

On the other hand, the form our's does not exist. Our on its own is already a possessive adjective -typically used before nouns- so it does never take possessive case 's.