Sed + needs to delete every line in the file starting with C ###

Question

How to delete a line that starts with three #

For example, you need to delete all of the following lines: from a file

1 ### bla bla bal

2 ### blablabla

3 ### blabla

. ,.

thanks Yael

Answer 1

you can also use awk

awk '!/^[ \t]*###/' file

Answer 2

cat file | sed '/^###/d'