Photography world has a portrait special. a three-pose portrait package has a sitting fee of $35, and a six-pose package has a sitting fee of $60. on a saturday, $690 was collected in sitting fees. which equation can be used to represent x, the number of three-pose portrait packages and y, the number of six-pose portrait packages? a.    360x  + 105y  = 690b.    35x  + 60y  = 690c.    105x  + 360y  = 690d.      60x  + 35y  = 690