Jospeh Stalin was the Soviet leader who brought all economic activity under the government's control.
Answer: D
Explanation:
The other 3 are worded poorly.
Answer:
The incorrect sentence is C. We should not buy grapes which scientists say are poisonous to dogs.
Explanation:
The commas should be placed like so,
We should not buy grapes which, scientists say, are poisonous to dogs.
I hope I helped!