Output of following Python code?
my_dict = {'a': 1, 'b': 2, 'c': 3}
new_dict = {}
for key in my_dict:
new_dict[key] = my_dict[key] ** 2
print(new_dict)
a) {'a': 1, 'b': 4, 'c': 9}
b) {'a': 1, 'b': 2, 'c': 3}
c) {'a': 2, 'b': 3, 'c': 4}
d) {'a': 1, 'b': 2, 'c': 3, 'd': 4}