(A): A high tension supply must have very large internal resistance
(R): A short circuited cell gives very high current, that may exceed safety limits of cell. 

Options

A. Both 'A' and 'R' are true and 'R' is the correct explanation of 'A'
B. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A'
C. 'A' is true and 'R' is false
D. 'A' is false and 'R' is false

Answer

A