What best describes the legal status of an object clause in a company's constitution that purports to limit certain types of business activity or transactions:

a.A company, unless it is a mining company is not permitted to have an objects clause in its constitution.

b. Any transaction that is outside the company's objects will be "ultra vires" the effect of which is that any such transaction will be void and unenforceable.

c. Object's clauses no longer invalidate transactions and are therefore pointless.

d. The transaction will not be invalid, however the constitution has effect as a statutory contract meaning that the objects clause could be enforced internally within the company.