💡 Detailed Explanation
'～わけにはいかない' means 'cannot do something' due to social, moral, or psychological reasons. In this sentence, the speaker cannot take the day off because of a social obligation (the important meeting), making 'わけにはいかない' the most suitable choice. 'ざるを得ない' means 'to have no choice but to do something' and would be used with a positive action like 'go to the office.' 'てはいられない' means 'cannot afford to be doing something,' expressing a sense of urgency. 'わけではない' is a partial negation ('it doesn't mean that...'), which does not fit the context.