The passover lamb was to be kept until the fourteenth was day of the first month...

During the Passover, the Israelites were instructed to choose a lamb without blemish and keep it until the fourteenth day of the first month. On that day, the whole assembly was to kill their lambs. The question is asking when they were supposed to kill the lambs.

Option A says "in the morning," but this is not correct. Option B says "at noon," but this is also not correct. Option D says "at midnight," but this is not correct either.

The correct answer is Option C: "in the evening." This means that the lambs were to be killed towards the end of the fourteenth day. This was done in remembrance of the time when God passed over the houses of the Israelites during the tenth plague in Egypt, sparing their firstborns because they had marked their doorposts with the blood of the lamb.

So, the Passover lamb was kept until the fourteenth day of the first month and was killed in the evening. This was an important tradition that the Israelites followed to remember their deliverance from Egypt.