The correct option to fill in the blanks in the sentence “If … one day we would talk about it for weeks” is C. a lion came into this room. So, the completed sentence is: “If a lion came into this room one day we would talk about it for weeks.”

Here’s why:

• A. a lion was coming into this room: This option is incorrect because “was coming” is used for an action that was happening at a specific time in the past. In this context, we are talking about a hypothetical situation, not a past event.

• B. a lion was coming into tis room: This option is incorrect because “tis” is a typo. It should be “this”.

• C. a lion came into this room: This is the correct option. “came” is used for a single, completed action in the past. In this context, it’s used to describe a hypothetical situation in the past.

• D. a lion is coming into this room: This option is incorrect because “is coming” is used for an action that is happening right now or generally true. In this context, we are talking about a hypothetical situation, not a current event.

• E. a lion is going to come into this room: This option is incorrect because “is going to come” is used to talk about future plans or intentions. In this context, we are talking about a hypothetical situation, not a future plan.