The correct answer is: Both statements are correct.
Statement I is correct because staff members are often in a position to provide valuable advice to line managers. They may have more experience in a particular area, or they may have a different perspective on the situation. Line managers should always listen to the advice of their staff, and they should consider it carefully before making a decision.
Statement II is also correct because line managers are ultimately responsible for the decisions that they make. They may choose to accept the advice of their staff, or they may choose to ignore it. If they choose to ignore the advice, they should be prepared to explain their reasons to their staff.
It is important to note that both statements are general statements, and there may be exceptions to them. For example, in some organizations, staff members may not be allowed to give advice to line managers. Additionally, line managers may not always be willing to listen to the advice of their staff. However, in general, both statements are correct.