Given the list manipulation below, what will list$1$ contain after execution?

list$1=[\text{'}a\text{'},\text{'}b\text{'},\text{'}c\text{'},\text{'}d\text{'}]$

list$2=$ list$1[$:$]$

list$2[1]=\text{'}x\text{'}$

A$)[\text{'}$a$\text{'},\text{'}$x$\text{'},\text{'}$c$\text{'},\text{'}$d$\text{'}]$

B$)[\text{'}$a$\text{'},\text{'}$b$\text{'},\text{'}$c$\text{'},\text{'}$d$\text{'}]$

C$)[\text{'}$a$\text{'},\text{'}$b$\text{'},\text{'}$x$\text{'},\text{'}$d$\text{'}]$