What is the correct meaning of ([-14,-14]) on the number line?

Correct answer: Only a closed point at (-14)

The direct answer is option A: only a closed point at -14. The interval [-14,-14] has the same number at both ends, so it contains exactly one real number: -14. Square brackets mean that the endpoint is included, and because both endpoints coincide, the interval collapses to a single point. Option A is therefore correct: draw one filled or closed dot at -14. Option B, an open circle, would represent exclusion of -14, as in an interval with round brackets, so it is wrong. Option C, the whole line, would be represented by (-∞,∞), not this one-point interval. Option D, no solution, is also wrong because -14 is included. A useful check is to ask which values lie between -14 and -14: only -14 itself. Remember that [a,a] represents the single value a.