File mode quiz

filemode.py

# hint: read this link before answering:
# https://stackoverflow.com/questions/1466000/difference-between-modes-a-a-w-w-and-r-in-built-in-open-function

with open("a.txt", "w") as f:
    f.write("abcd")

with open("a.txt", "r+") as f:
    f.write("x")
    x = f.read(1)
    print(x)

    f.write("y")
    x = f.read(1)
    print(x)

    f.write("z")
    x = f.read(1)
    print(x)

with open("a.txt", "r") as f:
    print(f.read())

# question: what is the output of this script?