The correct active voice of the given sentence is The minister hoisted the national flag.

The passive voice of the sentence is The national flag was hoisted by the minister. This sentence is in the simple past tense, which is used to describe an action that happened in the past. The passive voice of the sentence is formed by putting the subject of the active sentence after the verb "to be" and the past participle of the main verb. In this case, the subject of the active sentence is "the national flag" and the main verb is "hoist." The past participle of "hoist" is "hoisted." So, the passive form of the sentence is The national flag was hoisted by the minister.

The active voice of the sentence is formed by putting the subject of the passive sentence before the verb and removing the verb "to be." In this case, the subject of the passive sentence is "the minister" and the main verb is "hoist." So, the active form of the sentence is The minister hoisted the national flag.

The other options are incorrect because:

• The minister hoist the national flag. is grammatically incorrect. The verb "hoist" should not be used without the object "the national flag."
• The minister was hoisted the national flag. is grammatically incorrect. The verb "was hoisted" is not a correct verb form.
• The minister will hoist the national flag. is in the future tense, while the original sentence is in the simple past tense.