Which monotheistic religion is the oldest Islam Hinduism Christianity or Judaism?

Hinduism is not even close to being Monotheistic.

Judaism is the oldest, followed by Christianity and then Islam.

However, Muslims believe that their religion didn't begin with Mohammed, but that he was the final seal on it, and that Islam began in the time of Adam. Therefore, they could theoretically make a case in that department.

Historically, however, the first order is correct.