Placing restrictions on business opportunities through government lice

Placing restrictions on business opportunities through government licensing and other controls

(a) is not allowed now and never has been in American history.
(b) is not allowed now but was provided for by the Constitution and allowed until the 20th century.
(c) is allowed now but was not allowed during the colonial period nor in the decades immediately following the establishment of the new nation.
(d) has always been allowed in American history.

ANSWER

(d)