The correct option is 2) i.e B Explanation The present perfect continuous is used for an action that began in the past and still has relevance at the present time. Example: 'They have been building the boat for years.' (The verb 'building' denotes an action that began in the past and is still ongoing) Sentence: The world is yet to figure out the relevance of the problem, global warming had been a problem for the whole planet since the industrial revolution. ( Incorrect, the problem began in the industrial age and is still prevalent to date) Important Points The present perfect continuous is made up of two elements: the present perfect of the verb 'to be' (have/has been), and the present participle of the main verb (base+ing) Subject +has/have been +base+ing He has been Swimming The present perfect tense is used with adverbs and conjunctions to connect past events with the present time. Example: 'ever, just, recently, already, yet, so far, of late' Example: I have just finished my chores. (adverb 'just' is used to connect a past action that already occurred). ​Correct sentence: 'The world is yet to figure out the relevance of the problem, global warming has been a problem for the whole planet since the industrial revolution'