Which sentence does not contain any errors in comma usage?

a.
combine yogurt blueberries, and strawberries for a healthful smoothie.

b.
stephen arlo, and j. t. are on the three-person relay team.

c.
let's determine what to cook, when to serve dinner, and whether we should eat on the patio.

d.
as she walked through the woods, she noticed moss on stones on tree bark and along the path.

- "about the claims : -

making a claim is just a fancy way of saying that you're stating your main point.' claims are not just opinions. a claim tells what you think is true about a topic based on your knowledge .

about the country claims : -

a counterclaim is just the opposite of a claim. counterclaims are also provable and supportable by reasons and evidence. not just, 'because i said so.' when you're planning an argument, you need to know what the counterclaim might be so that you can make sure that you disprove it with your reasons and evidence your research." - (catherineroberts)

one is a red flower, and one is the sky when the sun sets.