Study the table given below:
Select the option where contraceptive/contraceptive method are correctly matched with their mode of action.
A – The pill: Inhibits ovulation (III).
B – Condom: Prevents sperm from reaching the cervix (I).
C – Vasectomy: Semen contains no sperm after the vas deferens is cut or tied (IV).
D – Copper-T: Prevents implantation of the fertilized egg (II).
A battery of emf \( E \) and internal resistance \( r \) is connected to a rheostat. When a current of 2A is drawn from the battery, the potential difference across the rheostat is 5V. The potential difference becomes 4V when a current of 4A is drawn from the battery. Calculate the value of \( E \) and \( r \).