Writing and reading files is an important aspect of many programs. Suppose you have to create a program that writes the number $0$ to a file c$\_$output.txt$,$ then later reads this file, and then adds the number back to the file.

Which code applies write and read methods appropriately to perform this task?

a$.)$

data$\_$w $=[0]$

fout $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$r$\text{'})$

for val in data$\_$w:

fout.write$($val$+\text{'}$

$\text{'})$

fout.close$()$

data$\_$r $=[]$

fin $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$w$\text{'})$

for values in fin:

val $=$ values

data$\_$r$.$append$($int$($val$))$

fin.close$()$

b$.)$

data$\_$w $=[0]$

fout $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$w$\text{'})$

for val in data$\_$w:

fout.write$($str$($val$)+\text{'}$

$\text{'})$

fout.close$()$

data$\_$r $=[]$

fin $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$w$\text{'})$

for values in fin:

val $=$ values

data$\_$r$.$append$($val$)$

fin.close$()$

c$.)$

data$\_$w $=[0]$

fout $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$r$\text{'})$

for val in data$\_$w:

fout.write$($str$($val$)+\text{'}$

$\text{'})$

fout.close$()$

data$\_$r $=[]$

fin $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$w$\text{'})$

for values in fin:

val $=$ values

data$\_$r$.$append$($int$($val$))$

fin.close$()$

d$.)$

data$\_$w $=[0]$

fout $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$w$\text{'})$

for val in data$\_$w:

fout.write$($str$($val$)+\text{'}$

$\text{'})$

fout.close$()$

data$\_$r $=[]$

fin $=$ open$(\text{'}$c$\_$output.txt$\text{'},\text{'}$r$\text{'})$

for values in fin:

val $=$ values

data$\_$r$.$append$($int$($val$))$

fin.close$()$