Your question: "The girl seems ________________ something for an hour."
Options C and D are obviously eliminated are "have been" and "being" are used to create the passive voice. The girl was doing something for an hour, and clearly, she is the subject who PERFORMED an action instead of receiving an action from someone or something else.
If Option A is used, the sentence is: "The girl seems to translate something for an hour." It does not make sense, as "to translate" means an intention to do something, yet "for an hour" here likely indicates that the translation has already taken place. (To elaborate on what I mean, if we change the sentence slightly: "The girl is to translate something for an hour.", then option A can be chosen as "for an hour" indicates a future duration.)
As you were writing the sentence, the girl must have completed her translation. When an action ended in the past but the effect is still ongoing, we use the present perfect tense (i.e. have translated). Hence, option B is the answer: "The girl seems to have translated something for an hour."
Just as a side discussion, Option D would be correct if the sentence were modified: Something was being translated (passive voice) by the girl for the past hour.
I hope this helps.