To solve this problem, we can use Charles`s Law, which states that the volume of a gas is directly proportional to its temperature, assuming constant pressure.

Given:

- The gas is compressed to half of its original volume at 27°C.

To find the temperature at which the gas will occupy its original volume again, we need to determine the temperature when the volume is halved.

According to Charles`s Law, if the volume is halved, the temperature should also be halved to maintain the proportionality.

So, if the gas is compressed to half of its original volume at 27°C, we need to heat it to 27°C/2 = 13.5°C to make it occupy its original volume.

Therefore, the temperature to which the gas should be heated to make it occupy its original volume is 13.5°C.

Please note that the options provided in the question (327°C, 600°C, 54°C, 300°C) do not match the correct answer calculated using Charles`s Law.