The correct option is D A-d; B-c; C-b; D-a
The SI unit of time is second (s). Other units are like minutes and hours. Some bigger units of time are days, weeks, years, decade, century and millennium. Relationship between various units of time is as follows:
1 minute = 60 seconds
1 hour = 60 minutes = 3600 seconds
1 day = 24 hours, so 3 days = 3×24 hours = 72 hours
10 years = 1 decade
100 years = 1 century
1000 years = 1 millennium