'Cling' is the base form of the verb, its past and past participle form is 'clung'. Cling is an irregular verb as its past and past participle form is not formed with the addition of -ed at the end of the base form of the verb.
Therefore, option B 'cling' and option D 'clung' are incorrect.
Option C  'cost' is also incorrect as its past and past participle form are 'cost' therefore it is an irregular verb.
The correct option is option A, 'cursed' as it is the past and past participle form of the verb 'curse'. It's a regular verb because we've simply added an -ed to form the past and past participle form of the base verb 'curse'.