Consider the following countries:

1. Armenia

2. Azerbaijan

3. Croatia

4. Romania

5. Uzbekistan

Which of the above are members of the Organization of Turkic States?

The correct option is 2 and 5.

To understand why this is correct, let us look at the details of the Organization of Turkic States (OTS):

The Organization of Turkic States (formerly known as the Turkic Council) is an intergovernmental organization established to promote comprehensive cooperation among Turkic-speaking states.

Member States:
The current full members of the Organization of Turkic States are:
1. Azerbaijan
2. Kazakhstan
3. Kyrgyzstan
4. Turkey
5. Uzbekistan

Observer States:
The observer states are:
1. Hungary
2. Northern Cyprus
3. Turkmenistan

Now, let us analyze the countries provided in the question:
• Armenia (1): It is not a member or observer state of the OTS.
• Azerbaijan (2): It is one of the founding members of the Organization of Turkic States (established via the Nakhchivan Agreement in 2009). Thus, Azerbaijan is a member.
• Croatia (3): It is not a member or observer state of the OTS.
• Romania (4): It is not a member or observer state of the OTS.
• Uzbekistan (5): It formally joined the organization as a full member in 2019. Thus, Uzbekistan is a member.

Therefore, only Azerbaijan (2) and Uzbekistan (5) are members of the Organization of Turkic States, which corresponds to the option 2 and 5.