Concept:"Caution" means careful behaviour to avoid danger or mistakes.
Explanation:The underlined word suggests acting with care and alertness.
A person who does something with caution pays full attention to what they are doing.
They try to prevent any risk or error before making a move.
"Quietly" refers to silence, not care.
"Quickly" means fast, and "slowly" means at a low speed — neither of these carries the idea of being watchful.
Therefore, the closest and most accurate option is "carefully".
Answer:B. carefully