A person who has been convicted of a felony may be sentenced to imprisonment for an indeterminate term as follows:
(1) In the case of a felony of the first degree, unless the statute provides otherwise, for a term of not less than five years and which may be for life.
(2) In the case of a felony of the second degree, unless the statute provides otherwise, for a term of not less than one year nor more than 15 years.
(3) In the case of a felony of the third degree, unless the statute provides otherwise, for a term not to exceed five years.