有以下程序：
#include＜iostream＞
#include＜math＞
using namespace std；
class point

private：
double x；
double y；
public：
point(double a,double B)

x=a；
y=b；

friend double distance (point a,point B) ；
；
double distance (point a,point B)

return sqrt((a.x-b.x)*(a.x-b.x)+(a.y-b.y)*(a.y-b.y))；

int main()

point p1(1，2)；
point p2(5，2)；
cout＜＜distance(p1,p2)＜＜end1；
return 0；

程序运行后的输出结果是

A．1

B．5

C．4

D．6

Holiday receipts—the total sales recorded in the fourth quarter of the year—determine the economic success or failure of many retail businesses. Camco, a retailer selling just one camera model, is an excellent example. Camco’s holiday receipts, on average, account for a third of its yearly total receipts and about half of its yearly profits.
If the statements above are true, which of the following must also be true about Camco on the basis of them

A．Its fixed expenses per camera sold are higher during the fourth quarter than for any of the other three quarters.

B．It makes more profit during the first and third quarters combined than during the fourth quarter.

C．Its per-camera retail price is lower, on average, during the fourth quarter than during any one of the first three quarters.

D．It makes less profit, on average, for a given dollar amount of sales during the first three quarters combined than during the fourth quarter.

E．(E) The per-camera price it pays to wholesalers is higher, on average, during the fourth quarter than during any of the other three quarters.