Which of the following is an example of the author's use of simile?
a. "it could have been the most ordinary family picture, except for the backdrop of white-wall tires."
b. "rays of sunlight streamed between the clouds, like the holy ghost on the cover of one of mattie's dead husband's magazines."
c. "…nervous white ribbons of lightning jumped between the mountaintops and the clouds."
d. "the whole tucson valley lay in front of us, resting in its cradle of mountains."