zinc is lighter than iron
zinc has lower melting point than iron
zinc has lower negative electrode potential than iron
zinc has higher negative electrode potential than iron
E0Zn2+|Zn= –0.76 VE0Fe2+|Fe= –0.44 VZn has higher negative SRP (Standard reduction potential) so it works as anode and protects iron to make iron as the cathode.Hence, option B is correct.