Citizenship can be acquired through various modes. Option 1, which includes only "i and ii" is incorrect because citizenship can also be acquired through other modes. Option 2, which includes "i, ii, and iii", is the correct answer. "i" refers to acquiring citizenship by birth, which means being born to citizens of a particular country. "ii" refers to acquiring citizenship through hereditary means, such as being born to citizens of a country regardless of the location of birth. "iii" refers to acquiring citizenship through registration, which typically involves applying for citizenship based on specific criteria set by the government. Option 3, which includes only "ii and iii", is incorrect because it excludes the mode of acquisition by birth. Option 4, which includes "iv, ii, and iii", is incorrect because it includes an incorrect mode of acquisition, which is by request. Alert - correct answer should be Option 2.