A Series Circuit Consists of a 100 V DC Power $\Omega$

Multiple Choice

A series circuit consists of a 100 V DC power source,a 100 $\Omega$ resistor,and a variable resistor of resistance R,which varies from 0 to 100 $\Omega$ .The current in the circuit is

A) directly proportional to R.
B) inversely proportional to R.
C) directly proportional to (100 $\Omega$ + R) .
D) inversely proportional to (100 $\Omega$ + R) .
E) neither directly nor inversely proportional to R or to (100 $\Omega$ + R) .