These properties were … sale before the fire gutted them.

Analyze the question: We need the phrase that correctly completes "These properties were ____ sale." The sentence is about properties that were being offered for sale before a fire destroyed them.

Explain the concept: In English, the idiom "up for sale" means something is available to be bought, i.e. it has been put on the market. Other related expressions are "on sale" (which usually means sold at a reduced price) and "for sale" (available to buy). Prepositions in idioms must be learned as fixed phrases.

Step-by-step solution:

• A. up for sale – a correct, standard idiom meaning "being offered for purchase." ✔
• B. up on sale – not an English idiom. ✘
• C. out for sale – not used in standard English. ✘
• D. down on sale – not an idiom. ✘

Full sentence: "These properties were up for sale before the fire gutted them." This means the properties were being offered on the market before the fire destroyed them. It fits perfectly in meaning and grammar.

Answer: A. up for

Exam tip: For preposition and idiom questions, don't try to reason by logic alone. Memorize common fixed phrases such as up for sale, up for grabs, up for discussion, on sale, for sale. Test each option by reading the full sentence aloud; the wrong ones usually sound unnatural immediately.