If a star whose declination is 60 N culminates at zenith, its altitude at the lower culmination, is

If a star whose declination is 60 N culminates at zenith, its altitud

1.	If a star whose declination is 60 N culminates at zenith, its altitude at the lower culmination, is
A.	10
B.	20
C.	30
D.	40
E.	60 .
Answer» D. 40