Answer: The correct answer is D. There is no sentence error.
Explanation: There is no mistake in the sentence provided, which is made up of an independent clause ("The Goliath beetle - weighing up to 3.5 ounces - is considered the biggest bug according to measures of weight") and a dependent clause ("even though it may come up short in contests of length or width"). Comma splice and run-on sentence only take place when two independent clauses are part of a sentence; therefore, this mistake does not apply to the sentence provided. Moreover, there is not a sentence fragment either because the sentence is complete and it expresses a full thought.