Help no links. Will mark Brainliest IF it's right.

experimental group I think:)

“the battle of stalingrad is not a turning point necessarily in strategic terms, because a lot more has to be done before the soviets can be certain of defeating germany,” says renowned world war ii historian richard overy. the germans had fought nearly a thousand miles across the soviet union to get to stalingrad.

yup! you are correct it is b.