Analyze the following code:

class Circle $\{$

private double radius;

public Circle$($double radius$)\{$

radius $=$ radius;

$\}$

$\}$

a$.$ The program has a compile error because it does not have a main method.

b$.$ The program does not compile because Circle does not have a default constructor.

c$.$ The program has a compile error because you cannot assign radius to radius.

d$.$ The program will compile, but you cannot create an object of Circle with a specified radius. The object will always have radius $0.$

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