1.Astronomers unveiled a new candidate Wednesday in their re

1.Astronomers unveiled a new candidate Wednesday in their research for an Earth-like planet outside our solar system in a 'habitable' zone,______just right for conditions that could support life.(C)
which B.that C.one D.one is
2.One doesn`t know,till one is a bit at odds with the world,_____one`s friends who believe in one rather generously,mean to one.(A)
A.how much B.whether C.how great D.when
3.It said ___security forces in Daraa were instructed not to carry weapons,and______armed groups fired on citizens and unarmed police when people left the Omari Mosque after prayers.(B)
A.that.../ B./.that C././ D.when.that