Decide if the following sentence is grammatically CORRECT or INCORRECT.

Er musste gesungen.

incorrect

correct

Er musste gesungen ist incorrect.

Gesungen is in the wrong form for the person Er

The correct answer is: incorrect.

The sentence, "Er musste gesungen," is missing the auxiliary verb "haben" to form the past tense. A correct version of the sentence would be "Er hat gesungen," which means "He has sung."

To decide if the following sentence is grammatically correct or incorrect, you would need to analyze the sentence structure and grammar rules of the German language.

The given sentence "Er musste gesungen." is incomplete and does not follow proper German grammar. In order for a sentence to be grammatically correct, it needs to have a subject, a verb, and a complete structure.

To make the sentence grammatically correct, you would need to add a direct object or a complete verb phrase. For example, you could add a direct object like "Er musste gesungen haben." (He had to have sung.) or you could complete the verb phrase like "Er musste gesungen werden." (He had to be sung.)

So, based on the incomplete structure of the given sentence, it would be considered grammatically incorrect.