Identical dielectric slabs are inserted into two identical capacitors `A` and `B`. These capacitors and a battery are connected as shown in figure. Now the slab of capacitor `B` is pulled out with battery remaining connected
A. During the process, charge flows from b to a
B. During the process, internal energy of the battery increases
C. Finally charge on capacitor B will be less than that on capacitor A
D. During the process, work is done by the external force F, which fully appears as heat in the circuit