If the variable line, 3x + 4y - A = 0 is such that the two circles x² + y² - 2x - 2y + 1 = 0 and x² + y² - 18x - 2y + 78 = 0 are on its opposite sides, then the set of all values of λin the interval:

(a) 12, 21
(b) (2, 17)
(c) (23, 31)
(d) 13, 23