The linear magnifications of the object in the conjugate positions of a convex lens are 4 and 2, respectively. The distance between the conjugate positions is 40 cm. This convex lens of glass (μ = 1.5) is immersed in water (μ = 1.33). The new focal length of convex lens in water is:

80 cm

The correct answer is Option (4) → 80 cm