My mother _____ French for 3 years when she was a kid.had been studyingwas studyinghas been studyingstudied

To determine the correct verb tense for the sentence, we need to analyze the context of the actions described.

1. Understanding the Context:

   • The phrase "for 3 years" suggests a duration that started in the past and likely continued for that entire period.
   • The sentence indicates that the action was completed at some point in the past.

2. Examining Verb Tenses:

   • Had been studying: This is the past perfect continuous tense, often used for actions that were ongoing up to a certain point in the past. However, it generally requires another action in the past to provide a point of reference, which is not indicated in this sentence.
   • Was studying: This is the past continuous tense, which indicates an ongoing action in the past but does not emphasize the duration as strongly as needed here.
   • Has been studying: This is the present perfect continuous tense, typically used for actions that started in the past and continue to the present, which doesn’t apply here.
   • Studied: This is the simple past tense, which indicates a completed action in the past.

3. Choosing the Best Option:

   • The most suitable choice is "studied," as it correctly conveys that the action was completed when she was a child.

Final Answer

My mother studied French for 3 years when she was a kid.