The correct option is D 4 ohm
Accorrdingtoquestion.......................Dependenceoftheresistanceisgiven,Rt=R0(1+at)⎡⎢
⎢
⎢
⎢⎣whereRtistheresistanceattempt.R0istheresistanceat00Candaisthetempraturecpefficient,sothat,5=R0(1+50a)6=R0(1+100a)now,dividingtheseequation,a=1200/celcious∴R0=4ohmandthecorrectoptionisD.