In 1915, amateur astronomer George Willis Ritchey designed a reflecting telescope that utilized a hyperbolic primary mirror to eliminate spherical aberration. This innovative configuration ______ represented a monumental leap forward in optical engineering, though it remained largely unappreciated until the launch of the Hubble Space Telescope decades later.
Which choice completes the text so that it conforms to the conventions of Standard English?
- —a design that was later refined by French astronomer Henri Chrétien—Answer
- B, a design that was later refined by French astronomer Henri Chrétien—
- C—a design that was later refined by French astronomer Henri Chrétien,
- Da design that was later refined by French astronomer Henri Chrétien,
Answer
The choice that uses matching em dashes to set off the nonessential phrase: '—a design that was later refined by French astronomer Henri Chrétien—'
The correct answer properly isolates the nonessential appositive phrase by using matching em dashes at both its beginning and its end. This conforms to standard punctuation rules for setting off parenthetical information.
Step-by-Step Solution
Key Concept
Punctuation of Nonessential Elements
Estimated Time:1m 0s