Explanation:

- The Industrial Policy Resolution (IPR), 1956, classified industries into three schedules.

- Schedule A listed industries exclusively reserved for the public sector.

- Schedule A included 17 industries.

- Schedule B contained industries where both the public and private sectors could operate, but the State would progressively take up a larger role.

- Schedule C included all other industries left open to the private sector.

- Option 2 (21) and Option 3 (15) are not correct; these numbers do not match any schedule of the IPR, 1956.

- Option 4 (2) is incorrect; only two industries were initially reserved in the 1948 Policy, not 1956.

Option 1: 17 is the correct answer.