InterviewBit Problems   Longest Common Prefix : Unsolved

Why does this throw an error of undefined reference (1)

A : [ "abcd", "abcd", "efgh" ] your function returned the following : expected ou (2)

Am i supposed to malloc memory for preparing the output string...? (2)

A : [ "ABCD" ] Your function returned the following : ABCD The expected returned (1)

What to do when you get internal error? (1)