The question asks us to choose the most appropriate words to fill in two blanks in a given sentence. The sentence is divided into two parts joined by "But". We need to consider the context of each part to determine the correct word.

Understanding Whether vs Weather

Let's understand the difference between the two words involved in the options:

• Whether: This word is typically used to introduce a clause expressing a doubt or choice between alternatives. It often follows verbs like 'know', 'ask', 'doubt', 'wonder', etc., or phrases implying uncertainty. For example, "I don't know whether he will come."
• Weather: This word refers to the state of the atmosphere, including temperature, precipitation, wind, etc. For example, "The weather is sunny today."

Filling the First Blank

The first part of the sentence is "I don't know ______ you would like my suggestion." The phrase "I don't know" indicates uncertainty. The blank needs a word that introduces a potential condition or outcome ("you would like my suggestion"). This is a perfect context for using "whether", which introduces a clause expressing doubt or possibility.

So, the first blank should be filled with "whether".

Filling the Second Blank

The second part of the sentence is "But the ______ is bad and you shouldn't go out at this time of the night." The context here is clearly about atmospheric conditions that make it unsuitable to go out at night. The word that refers to atmospheric conditions is "weather".

So, the second blank should be filled with "weather".

Choosing the Correct Option

Combining the words for the first and second blanks, we get "whether; weather". Now let's look at the given options:

• Option 1: Weather; weather
• Option 2: Weather; whether
• Option 3: Whether; weather
• Option 4: Whether; whether

Option 3 matches our determined combination "Whether; weather".

Therefore, the most appropriate option is 3.