Read the paragraph.

The Flag Day program was scheduled to take place on the playground’s blacktop. The chorus and the band had practiced patriotic songs, and the band was ready to march. The American flag was flying by the podium as the time for the program approached. Then without warning, the sky darkened and rain began to fall. Students proceeding toward the playground stopped and listened to the thunder and rain. Within minutes, an announcement came over the loudspeaker.

What problem is explained in the paragraph?

A.the patriotic songs
B.the preparation
C.the rainstorm
D.the announcement