💡 Detailed Explanation
The particle '〜のに' (noni) is a strong contrastive conjunction meaning 'although...', 'despite...', or 'even though...'. It goes beyond a simple contrast by conveying the speaker's emotional reaction, such as surprise, frustration, or dissatisfaction. It connects to plain forms, with na-adjectives and nouns requiring 'な'. The final clause cannot contain the speaker's direct volition or commands. In this sentence, it translates perfectly as: "He came to work despite being sick.". The correct option 'にも' dynamically matches the structural requirements and logical flow of the statement. The other options do not satisfy the grammatical construction or fail to convey the appropriate semantic nuance.