You are cloning using the pUC$19$ vector. After transforming E$.$ coli cells and plating them in the presence of ampicillin, you observe only white colonies on your plate? Which of the following is a possible explanation for this observation? $($choose all that apply$)$

a$.$ You forgot to digest the vector with the same restriction enzyme as your DNA insert

b$.$ You forgot to add X$-$Gal to your plate $x$

c$.$ All the E$.$ coli cells took up plasmid containing the DNA insert

d$.$ All the E$.$ coli cells took up plasmid that did not contain the DNA insert $x$