run linux command using execlp with more than one argument as string in c

Question

I am trying to run ls using system calls in C with more than one argument, for example -l -a. The arguments and their number is changing depending on the user input. The input is concatenated "-l" + "-a" == "-l -a". The code I'm using is:

execlp("ls","ls",arguments,NULL) //arguments = "-l -a"

The user input is from Terminal:

-l
-a