**Explanation:**

The list of industries reserved for the public sector in India is mentioned in the Industrial Policy Resolution, 1956. These industries are considered to be of strategic importance and are intended to be owned and operated by the government. However, over the years, there have been changes and certain industries have been excluded from this list.

The correct answer to the given question is option 'D' - Defense production. Defense production is no longer reserved for the public sector and can also be undertaken by private companies.

**Reason for Exclusion:**

The decision to exclude defense production from the list of industries reserved for the public sector was taken to encourage private sector participation, promote competition, and enhance efficiency and innovation in the defense industry. This move was aimed at attracting foreign direct investment (FDI) in defense manufacturing, modernizing the defense forces, and reducing the country's dependency on imports for defense equipment.

**Impact of the Decision:**

The exclusion of defense production from the list of reserved industries has led to the establishment of joint ventures, collaborations, and partnerships between Indian and foreign companies in the defense sector. This has resulted in the transfer of technology, knowledge sharing, and increased indigenous defense production capabilities.

Private companies are now able to participate in defense tenders, bid for defense contracts, and contribute to the development and production of defense equipment. This has not only boosted the growth of the private sector but has also created opportunities for employment and skill development in the defense industry.

The decision to allow private sector participation in defense production has also had a positive impact on the country's defense preparedness. It has led to the development and production of advanced defense equipment, weapons systems, and technology, thereby strengthening the country's defense capabilities.

In conclusion, defense production has been excluded from the list of industries reserved for the public sector in order to promote private sector participation, encourage competition, attract foreign investment, and enhance the country's defense preparedness.

Question is wrong all are included in public sector
defence can't be excluded from public sector because it is issue of national security