Select the correct active form of the given sentence.

Her phone can't be switched off by my father.

My father can't switch off her phone.

The correct active form of the given sentence "Her phone can't be switched off by my father" is My father cannot switch off her phone.

The passive voice of the sentence is "Her phone can't be switched off by my father." This sentence is in the present tense, but the action of switching off the phone is not happening now. The active voice of the sentence is formed by putting the subject of the passive sentence before the verb and removing the word "by." In this case, the subject of the passive sentence is "my father," and the verb is "switch." So, the active form of the sentence is "My father cannot switch off her phone."

The other options are incorrect because:

• My father switches off her phone." This sentence is in the active voice, but the verb is in the present tense, which does not match the tense of the passive sentence.
• My father could not switch off her phone." This sentence is in the past tense, but the action of switching off the phone is not happening now.
• My father have not switched off her phone." This sentence uses the wrong form of the verb "have." The correct form is "has."
• My father can't switch off her phone." This sentence is in the active voice, but the verb is in the negative form, which does not match the tense of the passive sentence.