Read this passage from "the oasis: africa": suddenly the sheikh stopped and pointed to the south. the caravan halted, and everyone prepared his arm. matchlocks were primed, cartridges rammed home, and swords loosened in their sheaths. was it the tuaregs again across our path? but mohammed, the keen-eyed, shouted joyfully— “the oasis, the oasis! i see the palm-trees.” in the passage, how does the tone shift? s: (a) the tone shifts from happy to sad. (b)the tone shifts from anxious to excited. (c)the tone shifts from angry to excited. (d)the tone shifts from sad angry.