Explanation:

- Shivaji did indeed send an ambassador to Bombay with intentions of negotiating an agreement with the English. This is historically accurate.

- His main objective was to secure support from the English against the Siddis of Danda-Rajpuri, which posed a threat to his kingdom.

- Additionally, he sought to acquire grenades, mortars, and other ammunition to strengthen his military arsenal.

Option 4 encompasses all the statements accurately:

- All three statements are correct as they collectively cover Shivaji's diplomatic and military strategies.

- Therefore, the correct answer is Option 4: 1, 2, and 3.