Replace the underlined word with the most appropriate SYNONYM.

For some time now, we’ve been toying with the idea of transferring all our business from
physical to online sales only

The correct option is considering.

Step-by-step Explanation:

1. Understand the meaning of the underlined phrase:
In the given sentence, the phrasal verb "toying with" is used in the context of "toying with the idea of transferring all our business". To "toy with" an idea means to think about it or consider it casually, without yet making a firm decision or commitment.

2. Analyze the given options:
- launch: This means to start or introduce something new (e.g., to launch a product or campaign). This is too active and does not match the tentative nature of "toying with".
- showing: This means displaying or demonstrating something, which does not fit the context of contemplating an idea.
- considering: This means thinking about something carefully, especially before making a decision. This is a direct synonym for "toying with" in this context.
- careful: This is an adjective meaning making an effort to avoid danger or mistakes, which is grammatically and semantically incorrect here.

3. Conclusion:
Replacing "toying with" with "considering" preserves the original meaning of the sentence perfectly: "For some time now, we've been considering the idea of transferring all our business..." Therefore, considering is the most appropriate synonym.