<span>The question is asking us "Which of the following pairs of ideas could be combined into a compound sentence?". For this, we need to find two sentences that are related and the answer is
C. The days became longer. The children could play outside later.
It is assumed here that children should be safe, so when they play outside, it should be daylight, and if the daylight is longer, they can also play outside longer than usually.</span>
