I agree with Kate ( Choice #2 is correct ). Number 3 is also acceptable, but not quite as accurate.
Option 2 is preferable - "Could not have" + verb (forseen) = because it addresses the situation using the conditional tense ef.edu/english-resources/english-grammar/conditional – RickyBobby yesterday
Option 3 is acceptable because the construction: I was unable to + VERB (present tense) is "softer" than: I could not + VERB (present tense). Option 1 is "so direct" - it would be how I would imagine Commander Data from Star Trek the Next Generation would discuss the situation – RickyBobby yesterday