If the length of the conductor is made 4 times its original length, its resistance becomes

Explanation

Resistance is proportional to length for a given cross section and material, so quadrupling the length quadruples the resistance. Note that if the wire were stretched to four times its length at constant volume, the area would fall to a quarter and the resistance would rise sixteenfold, which is the harder variant of this question. Here only the length is stated to change.