Which of the following is an inequality sentence?
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Step-by-step explanation:

Option A tells us that: When we add 5 to a variable x, we get 20. As it has a unique value for x and is completely equal to it(i.e. 15), It is an equality.Option B tells us that: A variable x equals to 5. Hence, as x is unique for 5 and is wholly equal to it, it's an equality too.Option C tells us that: A variable x isn't 5 but lesser than it. As we cannot equate it to 5, nor we are given the nature of the variable x, it is an Inequality.Option D is an expression; It can't be called an equation or an inequality unless we relate it with another expression.