Aca or acca


if it is possible can ay one answer my question please, i just have allitle bit question mark in my head, thw question is i just wanted to study aca rather than acca because i think it is better, but i just want to be sure which one is better and what is the distinguish acca and aca, and is aca exam easer than acca exam and how aca will help me to develop my career because i would like to became auditor and has aca exam open book, because my friend told me that aca has an open book exam

please can any one asnwer my question becase it is important for me