The correct answer is option 'C' - (i), (ii), and (iii).

The judiciary, or the court system, plays a crucial role in resolving disputes and upholding the law in a country. It serves as an independent body that interprets and applies the law to ensure justice and protect the rights of individuals and institutions. The judiciary has the power to hear and decide various types of disputes among different parties. Let's explore the options given and understand why option 'C' is the correct answer.

(i) Between citizens and the judiciary:
The judiciary is responsible for ensuring that citizens' rights are protected and that justice is served. If a citizen believes that their rights have been violated by the judiciary, they can approach the court to address their grievances. This includes cases of judicial misconduct, denial of fair trial, or any other issue related to the functioning of the judiciary.

(ii) Between citizens and the government:
One of the essential functions of the judiciary is to act as a check on the government's actions. If a citizen believes that their rights have been infringed upon by the government, they can approach the court for redressal. This can include cases of violation of fundamental rights, illegal government actions, administrative disputes, or any other matter where the government's actions are in question.

(iii) Between two or more state governments:
Disputes can arise between different state governments regarding various issues such as water sharing, boundary disputes, jurisdiction conflicts, or any other matter where the interests of the states are involved. In such cases, the judiciary can intervene to resolve the disputes and provide a fair and impartial judgment.

(iv) Between the government at the Union and the governments of other countries:
While the judiciary can play a role in interpreting international laws and treaties, disputes between the government at the Union and the governments of other countries typically fall under the domain of international law and diplomacy. Such disputes are generally resolved through diplomatic negotiations and international forums rather than domestic courts.

In conclusion, the judiciary can take up disputes between citizens and the judiciary, citizens and the government, as well as disputes between two or more state governments. Therefore, option 'C' - (i), (ii), and (iii) is the correct answer.