Find the correct item: When Billy went into the room he _______ smell burning. is able to must can could

When Billy went into the room, he could smell burning. — Когда Билли вошел в комнату, он почувствовал запах гари.Modal verb could is the past of can. We use could especially with: see, hear, smell, taste, feel, remember, understand. She spoke in a very low voice, but I could understand what she said.