Under what conditions current passing through the resistance R can be increased by short circuiting the battery of emf `E_2` ? The internal resistances of the two batteries are `r_1 and r_2`, respectively.
Options:
(a) `E_2r_1 > E_1(R + r_2)`
(b) `E_1r_2 > E_2(R + r_1)`
(c) `E_2r_2 > E_1(R + r_2)`
(d) `E_1r_2 > E_2(R + r_1)`