Which of the following 2 methods executes faster ?

class Trial {
String _member;
void method1() {
for(int i=0;i<2048;i++) {
_member += "test";
}
}
void method2() {
String temp;
for(int i=0;i<2048;i++) {
temp += "test";
}
_member = temp;
}
}
A. method1()
B. method2()
C. Both method1() and method2() takes same time for execution

Ans:   B