Which of the following is an example of a barrier to entry? (i) A key resource is owned by a single firm. (ii) The costs of production make a single producer more efficient than a large number of producers. (iii) Patents, copyrights, trademark laws, license to be the sole producer of a good (iv) The government has given the existing monopolist the exclusive right to produce the good. (1) and (it) only (ii) and (iti) only (i) only O (1), (1), and (iti) All of the above (i), (ii), (in) and (iv) Page 5 of 56