In the following passage, some words have been deleted. Read the passage carefully and select the most appropriate option to fill in each blank:
Researchers in quantum computing face the twin difficulties of (1)_____ qubit coherence and (2)_____ error rates. While superconducting qubits have shown promise, maintaining coherence beyond microseconds remains (3)_____ due to environmental decoherence. Furthermore, scaling up the number of qubits requires (4)_____ control electronics that themselves introduce noise. To overcome these hurdles, teams are exploring (5)_____ techniques such as surface codes and topological qubits.
What should come in the place of 2?
Show answer & explanation
Correct answer: B
Explanation
The passage describes "twin difficulties" in quantum computing. The first is maintaining qubit coherence, and the second refers to error rates. In this context:
Prohibitive means so high or difficult that it prevents something from happening.
High error rates are a major "difficulty" or hurdle that researchers must overcome, making "prohibitive" the most logically fitting adjective among the choices provided.
The other options (negligible, cheap, and low) describe positive or manageable conditions, which contradicts the "difficulty" mentioned in the text.