$3.$ The following code is supposed to take one letter as input, and count and print how many times

that letter appears in each string stored in a $2-$D grid. However, there is a semantic error in

this code that causes it to print incorrect values in some cases.

$1$ grid $=[["$zxy$",$"abc" $,$ "lmnop" $],$

$2["$an apple a day" $,$ "keeps doctors away" $,"$at least, as they say" $],$

$3["$lalala$",$ "loolooloo" $,$ "doopdedoop" $]]$

$4$

$5$ search $=$ input$("$Please type one letter$>")$

$6$ for row in range$($len$($grid$))$:

$7$ c $=0$

$8$ for col in range$($len$($grid$[$row$]))$:

$9$ for letter in grid$[$row$][$col$]$:

$10$ if letter $==$ search:

$11$ c $+=1$

$12$ print$($c$,$ end$="")$

$13$

$($a$)$ Write a specific input that is not affected by the error, and the corresponding correct

output produced by the program.

Input:

Output:

$($b$)$ Write a specific input that does trigger the error, and the corresponding incorrect output

produced by the program. This input should still be correctly$-$formatted: a single letter

string.

Input:

Output:

$($c$)$ What is the error, and how can it be fixed?

$3$