The correct Active/Passive form of the given sentence is:

☀ If we have to maintain our freedom, then we must fight for it.

Explanation for other options:

☀ If we had to maintain our freedom, then we must fight for it. This option changes the sentence to the active voice and alters the verb tense. It suggests a conditional situation in the past, which is not the intended meaning of the original sentence.

☀ If we had to maintain our freedom, then we have been fighting for it. This option changes the sentence to the active voice and does not maintain the original meaning. It suggests that we have been fighting for our freedom in the past, which is not the intended meaning of the original sentence.

☀ If we had been maintained our freedom, then we must fight for it. This option changes the sentence to the active voice and does not maintain the original meaning. It suggests a hypothetical situation in the past where our freedom has been maintained, which is not the intended meaning of the original sentence.