In this question, we are asked to identify which country does not share a common boundary with South Africa. Let`s analyze each option to find the correct answer.

Option 1: Zambia

Zambia is a landlocked country located in southern Africa. It shares a border with South Africa on its southernmost tip. Therefore, Zambia does have a common boundary with South Africa.

Option 2: Zimbabwe

Zimbabwe is a landlocked country located between South Africa and Zambia. It shares a common boundary with South Africa to the south. Therefore, Zimbabwe does have a common boundary with South Africa.

Option 3: Botswana

Botswana is a landlocked country in southern Africa. It shares a common boundary with South Africa to the east. Therefore, Botswana does have a common boundary with South Africa.

Option 4: Namibia

Namibia is a country located to the northwest of South Africa. It shares a common boundary with South Africa along a large portion of its eastern border. Therefore, Namibia does have a common boundary with South Africa.

From our analysis, we can see that option 1, Zambia, is the correct answer as it is the only country among the options that does not share a common boundary with South Africa.