(b) A trustee who accounts separately for a business or other activity may determine the extent to which its net cash receipts must be retained for working capital, the acquisition or replacement of fixed assets, and other reasonably foreseeable needs of the business or activity, and the extent to which the remaining net cash receipts are accounted for as principal or income in the trust's general accounting records. If a trustee sells assets of the business or other activity, other than in the ordinary course of the business or activity, the trustee shall account for the net amount received as principal in the trust's general accounting records to the extent the trustee determines that the amount received is no longer required in the conduct of the business.
(c) Activities for which a trustee may maintain separate accounting records include:
(1) Retail, manufacturing, service and other traditional business activities;
(2) Farming;
(3) Raising and selling livestock and other animals;
(4) Management of rental properties;
(5) Extraction of minerals and other natural resources;
(6) Timber operations; and
(7) Activities to which section 414 applies.