A cell of e.m.f. ε and internal resistance r sends current 1.0A when it is connected to an external resistance 1.9Ω. But it sends current 0.5A when it is connected to an external resistance 3.9Ω. Calculate the values of ε and r.
A. ε=2.0V,r=0.1Ω
B. ε=.1V,r=2.0Ω
C. ε=.2V,r=1.0Ω
D. Data insufficient