The correct answer is: 400 videos have been uploaded by Angel for English on YouTube.
The verb “to upload” means to transfer data from a computer or other device to a server or other online location. In this case, the data being uploaded is 400 videos. The verb “to be” is used in the passive voice to indicate that the action of uploading is being done to the videos, not by the videos. The past participle “uploaded” is used to form the passive voice.
The other options are incorrect because they do not use the passive voice. Option A, “are, uploaded,” uses the present tense, which is not appropriate for a completed action. Option B, “have, uploaded,” uses the present perfect tense, which is appropriate for a completed action but does not indicate that the action was done to the videos. Option C, “are been, uploaded,” is grammatically incorrect.
In conclusion, the correct answer is: 400 videos have been uploaded by Angel for English on YouTube.