Explanation:
The correct answer is option 'B' - Be optimistic.

The narrator denies us to be optimistic, which means the narrator discourages us from having a positive or hopeful outlook on things. This denial can be seen as a negative attitude towards optimism and a preference for being realistic or pessimistic.

Reasoning:
To understand why the correct answer is option 'B', let's analyze the other options one by one:

a) Be realistic: The narrator does not deny us to be realistic. In fact, being realistic is often seen as a desirable quality as it allows us to face the truth and make well-informed decisions. Therefore, option 'a' is incorrect.

b) Be optimistic: The narrator denies us to be optimistic. This means that the narrator discourages us from having a positive or hopeful outlook on things. This denial can stem from a belief that being optimistic leads to unrealistic expectations or a lack of preparedness for potential challenges. Therefore, option 'b' is correct.

c) Keeping our watch accurate: There is no mention of the narrator denying us to keep our watch accurate. This option is unrelated to the narrator's denial, and therefore, option 'c' is incorrect.

d) Wake up when we are supposed to: There is no mention of the narrator denying us to wake up when we are supposed to. This option is also unrelated to the narrator's denial, and therefore, option 'd' is incorrect.

Conclusion:
In conclusion, the narrator denies us to be optimistic, as indicated in option 'B'. This denial suggests a negative attitude towards optimism and a preference for being realistic or pessimistic.