Which sentence uses commas correctly?

a.
well, what can we do to fix the tire?

b.
yes you may use my pen.

c.
oh the smallest monkeys in the world stand only five inches high.

d.
why that's the last time i'll ever eat at this restaurant.

either online or traditional classroom can work for students. which is better will depend on students and teacher. students may have trouble following a lesson in classroom while they can study at their own pace online. other students may have trouble staying focus on their own in online classes. teachers are more used to classroom teaching but they may also be more worry about their jobs teaching online classes and work harder.