Read the definitions, then choose the word that correctly completes the sentence. In - = not aud = to hear - ible = can be done - ity = state or condition of My grandfather spoke so quietly that his words were almost audible. Audibility. Inaudible. Inaudible.

The word that correctly completes the sentence is inaudible.

Inaudible means that something is not audible or it cannot be heard. Since the grandfather spoke so quietly, it was difficult to hear them. Therefore, the sentence should read, "My grandfather spoke so quietly that his words were almost inaudible.

The answer would be C. Inaudible.