What is the output of these lines of code?

Consider the following lines of code:
$_ = “This is a test”;
s/^([^ ]*)\s*([^ ]*)/$2 $1/;
print;
What is the output of these lines of code?

A.
hTis a test

B.
isThis a test

C.
i Thiss a test

D.
his T is a test