Which sentence contains the best example of parallelism? A. To an experienced climber, the ascent of the first peak was a gentle half day's journey, but further challenges lay in wait.
B. One of the guides fell ill, and the next day we heard that our leader would not be able to join—and this was only days before we were scheduled to begin the climb.
C. Because the climb was so complex, our leader proposed that we start by mapping the route, analyzing its challenges, and making backup plans.
D. To prepare for the climb, Maya went to the gym regularly, adding climbing classes to her strength training and other routines.