Which of the Following Propositions Uses Punctuation to Indicate Whether

Which of the following propositions uses punctuation to indicate whether a relative clause is restrictive or nonrestrictive?

A) Oranges, lemons, grapefruits, and limes are all citrus fruits.
B) Welders, who are highly skilled laborers, are in high demand.
C) Dragons, according to legend, can fly and breathe fire.
D) Pi (3.14159 ...) has an infinite, nonrepeating decimal value.
E) The Great Lakes include Huron, Michigan, Ontario, Erie, and Superior.