What would following expression return?(a)"Hello World".upper().lower()

Q. What would following expression return?

(a) "Hello World".upper().lower()

(b) "Hello World".lower().upper()

(c) "Hello World".find( "Wor", 1, 6)

(d) "Hello World".find( "Wor")

(e) "Hello World".find( “wor”)

(f) "Hello World".isalpha()

(g) "Hello World".isalnum()

(h) "1234".isdigit()

(i) "123FGH".isdigit()

You can understand by Watching video :-

Answer :-

(A) = 'hello world'
(B) = 'HELLO WORLD'
(c) = -1
(D) = 6
(E) = -1
(F) = False
(g) = True
(h) = True
(I) = False