Which of the following is the first sentence of the passage?

Seven statements are given below, which are jumbled in any random order. Only the seventh statement (g), which has been emboldened, is in its correct place. These statements will form a coherent and meaningful paragraph, when arranged in the correct sequence. Arrange the sentences in the right order and answer the questions that follow. (a) Each year during ozone hole season in late September through mid-October, NOAA scientists at the South Pole release weather balloons that drift into the stratosphere and measure how much ozone is present at different altitudes in the atmospheric column. (b) In late October, NOAA and NASA scientists reported that the ozone hole that develops in the stratosphere over Antarctica every spring was larger and deeper than average in 2021. (c) It was also smaller than it would have been without the Montreal Protocol—the international treaty to stop the production of ozone-destroying chemicals called CFCs. (d) For many years, balloons found parts of the stratosphere with no detectable ozone during the peak ozone loss period. (e) But there was also good news: the hole in our planet’s UV-blocking ozone layer was smaller than those of the 1990s and 2000s. (f) The scientists sarcastically said that it was all thanks to a colder-than-average winter. (g) In only a handful of years did balloons find ozone ___________ (5) the entire column, without any zero-ozone regions.