Task: Instance Description Understanding (ontology: Sciences/Computer_Science)

Which of the following definitions best describes the instance 'week'?

A. A time unit which is equal to 7 days.
B. A time unit which is equal to 60 seconds.
C. A time unit which is equal to 12 months which is science is taken to be equal to 365.25 days.
D. A time unit which is equal to the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.

Answer: A time unit which is equal to 7 days.