PTE Scored Mock TEST: Reading

Multiple Choice Questions: Single

Read the text and answer the multiple-choice question by selecting the correct response. Only one response is correct.

I felt the wall of the tunnel shiver. The master alarm squealed through my earphones. Almost simultaneously, Jack yelled down to me that there was a warning light on. Fleeting but spectacular sights snapped into and out of view, the snow, the shower of debris, the moon, looming close and big, the dazzling sunshine for once unfiltered by layers of air. The last twelve hours before re-entry were particular bone-chilling. During this period, I had to go up into command module. Even after the fiery re-entry splashing down in 81o water in south pacific, we could still see our frosty breath inside the command module.

Which one of the following reasons would one consider as more as possible for the warning lights to be on?