Both "benefit to" and "benefit of" are grammatically correct, but they are used in different contexts: Benefit to: This phrase typically indicates that something provides an advantage or positive outcome to someone or something. For example, "The new policy provides a benefit to employees." Benefit of: This phrase is often used to refer to the advantage or positive aspect derived from something. For example, "One benefit of regular exercise is improved health." Choose the one that best fits the context of your sentence!

Better to say "...the benefits of..." Your first two sentences are better than the third, but they all sound awkwardly worded. We wouldn't really use this construction: "...their benefits of/in/to ..." In a simpler sentence, it's fine to say "their benefits", for example "Don't forget their benefits!" But when the sentence continues and complicates the grammar, for clarity we tend to say something more like "...the benefits of/in..." ('of' and 'in' both work fine here). We wouldn't say "to" in the same way - it's an inappropriate word in this structure. But we could say "from", although it's a bit strong as if you can predict the future, so it's more likely to be accompanied by other words, such as "the likely/probable/expected benefits derived from them reducing the cost of..."

Great question! The correct preposition depends on how you structure the sentence. ✅ "I highlighted their benefits in reducing the cost." → This is the best option. "Benefits in" is used when referring to the advantages of an action or process. 🚫 "I highlighted their benefits of reducing the cost." → "Benefits of" is usually followed by a noun (e.g., the benefits of exercise), but "reducing" is a verb form. 🚫 "I highlighted their benefits to reduce the cost." → This is awkward. "Benefits to" is sometimes used (e.g., the benefits to society), but in your sentence, it sounds like the benefits themselves are reducing the cost, which is unclear. So, "benefits in reducing the cost" is the most natural and grammatically correct choice. 😊

Not knowing what you mean to say, it is impossible for me to make any choice.

i highlighted THE benefits OF reducing costs