Select the correct answer. Which sentence best states how the author develops his thesis?

A.
The author answers an introductory question.
B.
The author provides examples and evidence.
C.
The author gives examples and restates the thesis.
D.
The author provides evidence from experts.

excerpt adapted from Canyons of the Colorado
by John Wesley Powell

The wonders of the Grand Canyon cannot be adequately represented in symbols of speech, nor by speech itself. The resources of the visual arts are taxed beyond their powers in attempting to portray its phenomenal beauty. Language and illustration combined must fail. The elements that unite to make the Grand Canyon the most sublime spectacle in nature are many and exceedingly diverse. The giant forms, which result from the sculpture of tempests through ages too long for man to compute, are wrought into endless details. To describe these forms would be a task equal in magnitude to that of describing the stars in the sky or the abundant beauties of the forest with its traceries of foliage presented by oak and pine and poplar, by beech and linden and hawthorn, by tulip and lily and rose, by fern and moss and lichen. Besides the elements of form, there are elements of color. The rainbow is not more replete with hues. But form and color do not exhaust all the divine qualities of the Grand Canyon. It is the land of music. The river thunders in perpetual roar, swelling in floods of music when the storm rains play upon the rocks, and fading away in soft and low murmurs when the infinite blue of the sky is unveiled. With the melody of the great tide rising and falling, swelling and vanishing forever, other melodies are heard in the gorges of the lateral canyons, while the waters plunge in the rapids among the rocks or leap in great cataracts. Thus, the Grand Canyon is a land of song. Mountains of music swell in the rivers, hills of music billow in the creeks, and meadows of music murmur in the rills that ripple over the rocks. Altogether it is a symphony of diverse melodies. All this is the music of waters. The adamant foundations of the earth have been wrought into a sublime harp, upon which the clouds of the skies play with mighty tempests or with gentle showers.