A hollow double concave lens is made of very thin transparent material. It can be filled with air or either of two liquids L1 or L2 having refractive indices μ1 and μ2 respectively ( μ2>μ1>1 ). The lens will diverge a parallel beam of light if it is filled with [2000S]
a. air and placed in air
b. air and immersed in L1
c. L1 and immersed in L2
d. L2 and immersed in L1