Select the option that expresses the given sentence in active voice.

Pygmalion was written by GB Shaw.

GB Shaw wrote Pygmalion.

The correct option that expresses the given sentence in active voice is GB Shaw wrote Pygmalion.

The other options are incorrect because:

• Pygmalion was written by GB Shaw is in the passive voice.
• GB Shaw was writing Pygmalion is in the present progressive tense, while the original sentence is in the past tense.
• GB Shaw was written by Pygmalion is grammatically incorrect. The subject of the sentence is "GB Shaw," which is not a thing that can be written.
• Pygmalion wrote GB Shaw is grammatically incorrect. The verb "wrote" is in the active voice, but the subject is not the one doing the action.