You are given a mathematical question described with an open-ended vocabulary. Questions in this task involve real-world situations, describing a mathematical problem. You are also given 4 or 5 answer options (associated with "A", "B", "C", "D", "E"). Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D', 'E'. LaTeX mathematical format (the standard way to express mathematical expressions in the typesetting software known as LaTeX) is used to express equations. Each question is solvable with high school math knowledge. Give only one answer for each question.

[Q]: A radio station emits a signal that can be received for 60 miles in all directions. If the intensity of the signal is strengthened so the reception increases by 40 miles in all directions, by approximately how many square miles is its region of reception increased?
(A)6,300 (B)10,000 (C)10,300 (D)20,000 (E)31,400
[A]: D


[Q]: Nora has 10 fewer than twice the number of CDs that Deborah has. If n represents the number of Nora's CDs, and d represents the number of Deborah's CDs, which of the following is a correct equation relating n and d ?
(A)\(n = 2d - 10\) (B)\(n = 2(d - 10)\) (C)\(n = 10 - 2d\) (D)\(n = 2(10 - d)\) (E)\(n = 10 - (d +2)\)
[A]: A


[Q]: Cathy's average rate during the Boston Marathon was 10 minutes a mile for the first \(b\) hours where \(b < 4\). In terms of \(b\), how many more miles does Cathy have to run to complete the 26-mile race?
(A)\(26 - 6b\) (B)\(26 - 600b\) (C)\(6b - 26\) (D)\(26 - \frac { 6 } { b } \) (E)\(\frac { 26 - b } { 6 } \)
[A]:
A