Translation:I have it
Note that the verb prefix (vI-) includes information on both the grammatical subject and grammatical object. Many human languages only conjugate the verb for subject, so an object pronoun becomes necessary to have any idea at all what object use being used. In Klingon, since the object is also indicated by the verb prefix, adding an object pronoun provides little additional information and the object pronouns are often left off, as you see in the sentence given by Duolingo.
In Klingon, you can drop pronouns like 'oH when they're the subject or object of a verb and they're clearly understood in context.
Klingon 1: nuHwIj Daghaj'a'? (Do you have my weapon?)
Klingon 2: vIghaj (I have it.)
Klingon 2 could have said 'oH vIghaj, but he didn't need to because it was obvious from the context what it was meant.