Manu ..... since 9 o'clock.AsingsBsingCis singingDhas been singingAnswer: D. has been singing Read Explanation: since എന്ന പദം ഉള്ളതിനാൽ present perfect continuous tense ൽ ആണ് sentence വരുന്നത്.has been singing എന്നതാണ് present perfect continuous tense ൽ വരുന്ന verb .Read more in App