'X' through an advertisement offered to give a reward of Rs.5000 to anyone who would bring back his lost son. 'Y' brings the son of 'X'. In which of the following circumstances 'Y' ' would be entitled to the reward?

• A. When he has read the advertisement and started searching for the son and brought him
• B. When he started looking for the son, he did not know about the reward but about the advertisement before he brought the son
• C. When he did not even know about the advertisement till the time he brought the son to 'X'
• D. none of the above