Concept:
When comparing unit fractions (fractions where the numerator is exactly 1), the size of the fraction is completely determined by its denominator.
• Inverse Relationship Rule: For fractions with identical positive numerators, the fraction with the smaller denominator holds the larger total value because a single unit is being divided into fewer pieces.
• Conversely, the fraction with the larger denominator will have a smaller net value.
Step 1: Analyzing and ordering the denominators.
Let's list out all denominators present in the set of given fractions:
\[
\text{Denominators: } 5, \, 4, \, 11, \, 13
\]
Arranging these positive integers in ascending order (from smallest to largest):
\[
4 < 5 < 11 < 13
\]
Step 2: Applying the reciprocal rule for fractions.
Since the denominators follow the order \(4 < 5 < 11 < 13\), taking the reciprocal reverses the inequality signs completely:
\[
\frac{1}{4} > \frac{1}{5} > \frac{1}{11} > \frac{1}{13}
\]
From this clear ordered inequality sequence, it is visually apparent that the fraction \( \frac{1}{4} \) stands as the largest value among all elements in the set.
Step 3: Verification via decimal conversion.
Let us perform the explicit division for each option to convert them into standard decimal notation:
\frac{1}{4} &= 0.250
\frac{1}{5} &= 0.200
\frac{1}{11} &\approx 0.091
\frac{1}{13} &\approx 0.076
Comparing the values: \(0.250 > 0.200 > 0.091 > 0.076\). This confirms that \( \frac{1}{4} \) is the greatest number, aligning with Option (B).