The correct answer is option 4, which is 18 years. In India, the minimum qualifying age to be a voter is 18 years. This means that individuals who are 18 years old or above are eligible to register as voters and participate in the democratic process by casting their votes during elections. It is important to note that this age requirement may vary in different countries, as each country sets its own criteria for voter eligibility. In India, the minimum age of 18 years is determined in order to ensure that a significant proportion of the population, including young adults, have the opportunity to exercise their right to vote and have a say in the nation`s governance.