The preposition "against" is used when something is in contact with another surface for support.
The correct sentence should be:
"He leaned against the wall for support."
Thus, the correct answer is Option A ("against").
Each question has a sentence that has an underlined part. Choose the option which rephrases the underlined part in the most appropriate manner in terms of grammar and usage.
In an attempt to boost their profits, many edible oil-producing companies have been engaging themselves in propaganda against commonly used oils and promoting exotic and expensive varieties of oils \(\underline{as\ more\ healthier\ options.} \)