A program contains the following procedures for string manipulation.

Procedure Call

Explanation

Concat $($strl$,$ str$2)$

Returns a single string consisting of stri followed by str$2.$ For example, Concat $("$key$",$ "board" $)$ returns "keyboard".

Substring $($str$,$ start, length$)$ Returns a substring of consecutive characters from str$,$ starting with

the character at position start and containing length characters.

The first character of str is located at position $1.$ For example, Substring $("$delivery$",3,4)$ returns "live"

Which of the following expressions can be used to generate the string "Happy"?

A Concat $($Substring $("$Harp$",1,1),$ Substring $("$PuppY$",2,4))$

B Concat $($Substring $("$Harp$",1,2),$ Substring $("$Puppy$",3,3))$

$$ Concat $($Substring $("$Harp$",1,2),$ Substring $("$Puppy$",4,2))$

D Concat $($Substring $("$Harp$",2,2),$ Substring $("$Puppy$",4,2))$