What will be the output of the following Python code?

x = 'abcd'
for i in x:
    print(i.upper())

In the given code, a string 'abcd' is assigned to the variable x.
Then, a for loop iterates over each character in the string x.
For each character i, the upper() method is called to convert it to uppercase.
The upper() method converts a string to uppercase.
Therefore, the output will be each character of the string 'abcd' converted to uppercase and printed on separate lines:
A
B
C
D.