Topic: Conditional Sentence,

Best Answer Explained in Below-:

The sentence "I always take an umbrella — it rains." implies a conditional relationship between taking an umbrella and the occurrence of rain. The phrase "incase" serves to indicate preparation for a potential situation or event. In this context, "incase" suggests that the speaker takes an umbrella as a precautionary measure whenever rain is likely or anticipated.

Examining the options, “incase” (A) is the most suitable choice because it communicates the speaker's proactive approach to a recurring condition (rain), reinforcing the idea of being prepared for unexpected weather.

Option B, "incase of," is grammatically incorrect in this specific construction. "If" (C) could suggest a more uncertain scenario, while "unless" (D) implies a conditional that would negate the action of taking an umbrella, which does not align with the speaker's established habit.

Overall, the use of "incase" in the sentence encapsulates the speaker's readiness for rain, making it the correct choice for conveying the intended meaning of the statement.