This article shall not apply to:

1. (a) Insurers made exempt therefrom by other provisions of this code.
2. (b) Insurance upon the interests of common carriers engaged in interstate trade, or upon property in their custody.
3. (c) Insurance contracts executed without this state, but which during the term thereof temporarily cover subject matter within this state.
4. (d) Bid bonds issued by any admitted insurer in connection with any public or private contract.