Which sentence could appear in a conclusion is it? You should take care with your personal information on travel websites or booking your travel online and short can add up to significant savings or there are numerous specialized travel websites that cater to different travelers or is booking your vacation online the best way to save.

All of these sentences could potentially appear in a conclusion, as they summarize the main points made in the body of an essay or article. However, the sentence "You should take care with your personal information on travel websites or booking your travel online and short can add up to significant savings" seems slightly out of place compared to the others, as it focuses more on warning readers about personal information security rather than summarizing the main ideas discussed.

The sentence that could appear in a conclusion is: "Booking your vacation online is the best way to save."

The sentence that could appear in a conclusion is:

"Booking your vacation online may be the best way to save."

To figure this out, we need to understand that a conclusion is a section where the main points or findings of an argument or text are summarized. In the given options, this particular sentence is a summary of the main argument discussed in the text. It suggests that booking your vacation online is a recommended way to save money. Hence, this sentence can be considered as part of a conclusion.