Flying east across the International Date Line can be a bit confusing, but the correct answer is option 4 - you will lose 24 hours. The International Date Line is an imaginary line that roughly follows the 180° longitude line in the Pacific Ocean. When you cross this line from west to east, you essentially move forward in time, which means you "lose" a day.

To understand this, let`s consider an example: Imagine that you are flying from Los Angeles, which is on the west coast of the United States, towards Tokyo, Japan. As you fly east across the International Date Line, you are moving ahead in time. So, if it is Monday in Los Angeles, when you cross the International Date Line, it suddenly becomes Tuesday in Tokyo. Therefore, you "lose" a day.

It`s important to note that the 24-hour time difference doesn`t mean you lose a full day of your life. It simply means that the calendar date changes as you cross the International Date Line. So, in practical terms, if you were to leave Los Angeles on Monday morning, you would arrive in Tokyo on Tuesday morning (local time).

So, option 4 is the correct answer - you will lose 24 hours when flying east across the International Date Line