After working from 10 a.m. to 5 p.m. on a Thursday as one of 5,000 employees in a beer factory, A hurried home to catch the early evening news and have dinner with his family. At around 10 p.m. of the same day, the plant manager called and ordered A to fill in for C who missed the second shift.

(a) May A validly refuse the plant manager's directive? Explain.
(b) Assuming that A was made to work from 11 p.m. on Thursday until 2 a.m. on Friday, may the company argue that, since he was two hours late in coming to work on Thursday morning, he should only be paid for work rendered from 1 a.m. to 2 a.m.? Explain. (2010 BAR)