Britain’s dependency on certain essential services has greatly widened and become a key role in the country’s ______.

[A] Preparing for an important test.
B. Funding for university education. [c] Winning the confidence of voters.
D. Graduate school application procedures.

A．Music they like can relieve depression but distract attention.
B．Music they like can reduce stress and improve concentration.
C．Classical music and rock-and-roll increase their heart rate and expand the breathing.
D．Wearing headphones can help concentrate when they are performing operations.