Given the fact "one year is equal to 365 days", what is the answer to the question or completion "Needing to predict planting and harvesting times and when certain food animals would hibernate, early humans learned repeating weather patterns, star formations and time intervals to realize that"

pick from the following.
(a). the sky is usually blue at night;
(b). most plants take a year to grow;
(c). one year consists of 365 days and nights;
(d). the sun is still for 12 months a year;
(c).