I ..... him since childhood.Ahas knownBhave knownChas been knowingDhave been knowingAnswer: B. have known Read Explanation: since എന്ന പദം ഉള്ളതിനാൽ present perfect continuous tense ൽ ആണ് sentence വരുന്നത്.'has known','have known' എന്നതാണ് present perfect continuous tense ൽ വരുന്ന verb .ഇവിടെ subject I ആയതിനാൽ plural verb ആയ have known ഉപയോഗിക്കുന്നു.Read more in App