There are actually 27 countries that start with letter S, but since the choices do not include 27, we will go with the number 26. The following countries are:
1. Saint Kitts and Nevis with an estimated population of 56,780 people;
2. Saint Lucia with an estimated population of 187,768 people;
3. Saint Vincent and the Grenadines with an estimated population of 109,895 people;
4. Samoa with an estimated population of 195,743 people;
5. San Marino with an estimated population of 32,104 people;
6. Sao Tome and Principe with an estimated population of 198,481 people;
7. Saudi Arabia with an estimated population of 32,742,664 people;
8. Senegal with an estimated population of 16,054,275 people;
9. Seychelles with an estimated population of 97,539 people;
10. Sierra Leone with an estimated population of 6,732,899 people;
11. Singapore with an estimated population of 5,784,538 people;
12. Slovakia with an estimated population of 5,432,157 people;
13. Slovenia with an estimated population of 2,071,252 people;
14. Solomon Islands with an estimated population of 606,215 people;
15. Somalia with an estimated population of 11,391,962 people;
16. South Africa with an estimated population of 55,436,360 people;
17. South Korea with an estimated population of 50,704,971 people;
18. South Sudan with an estimated population of 13,096,190;
19. Spain with an estimated population of 46,070,146 people;
20. Sri Lanka with an estimated population of 20,905,335 people;
21. Sudan with an estimated population of 42,166,323 people;
22. Suriname with an estimated population of 552,112 people;
23. Swaziland with an estimated population of 1,320,356 people;
24. Sweden with an estimated population of 9,920,624 people;
25. Switzerland with an estimated population of 8,454,083 people; and
26. Syria with an estimated population of 18,906,907 people.
An additional country would be Serbia, but it is not probably counted as a country because it used to be part of Yugoslavia until 1990, then it formed a union with Montenegro until 2006. It was only in 2006 that Serbia established its independence and became officially known as Serbia or the Republic of Serbia.
