A study claims that the average temperature on Earth has permanently increased, because the average temperature each year for the last five years has been higher than any previous yearly average on record. However, periods of up to ten years of average temperatures that have consistently been record highs are often merely part of the random fluctuations in temperature that are always occurring. Which one of the following is most strongly supported by the information above? ['Five successive years of increasing annual average temperature does not always signify a permanent increase in temperature.', 'Record high temperatures can be expected on Earth for another five years.', 'The average temperature on Earth never increases except in cases of random temperature fluctuation.', 'All large increases in average temperature on record have occurred in ten-year periods.']