In the first question regarding the figure of speech shown in the paragraph, the correct answer is verbal irony. Lucia's comment, "Happy birthday to me," in light of the unfortunate event of getting splashed with mud, is an ironic statement because it contrasts with the expectation of a happy birthday.
For the second question about which sentence contains an example of verbal irony, the correct response is:
"I guess this is going to be a group effort," Han said, looking at the full sign-up sheet.
This reflects verbal irony as Han's statement suggests cooperation, while the full sign-up sheet likely indicates a lack of involvement from others.