unsteady yet independent and capable. Yet light didn't fill Mrs. Santiago's face; instead, her face was a mask of dark clouds. "Outstanding, Manuel!" I congratulated. That run started out as it usually did, my father lengthening the distance between us, a flexible rubber band, stretching and extending. Iran harder, anticipating the familiar stitch in my side, but it didn't develop. I picked up the pace slightly when I became conscious that the distance between us was closing, not lengthening. Fewer than fifty meters separated us.

.What does the author mean on page 4 by saying that Mrs. Santiago's "face was a mask of dark clouds"?
Mrs. Santiago felt sad that Manuel was becoming more independent.
Mrs. Santiago realized Manuel wanted to do other things than ride a bike.
Mrs. Santiago felt unsure of her ability to teach Manuel to ride a bike.
Mrs. Santiago wanted Manuel to learn how to be a runner like Carolina. ​