The correct answer is: C. Either I or II is implicit
The statement says that the channel will contact the viewers between 9.00 a.m. to 6.00 p.m. on weekdays and the lucky ones will be given fabulous prizes. This means that the viewers need to be available to receive the phone call. This implies that they may remain indoors to receive the phone call. It also implies that more people may start watching the programme in order to be eligible for the prizes.
However, the statement does not explicitly state that the viewers will remain indoors or that more people will start watching the programme. Therefore, we cannot say for certain that either assumption is true. We can only say that either assumption is possible.