Formal:
* দুঃখিত, বিলম্বের জন্য। (Dukhito, bilamber jonno) - This is the most formal way to say sorry for the delay.
* ক্ষমা করবেন, বিলম্বের জন্য। (Khoma korben, bilamber jonno) - This is also a formal way to apologize for the delay.
Informal:
* দুঃখিত, দেরী হয়ে গেল। (Dukhito, deri hoye gelo) - This is a more casual way to say sorry for the delay.
* ক্ষমা করো, দেরী হয়ে গেছে। (Khoma koro, deri hoye geche) - This is another informal way to apologize for the delay.
More casual:
* আচ্ছা, দেরী হয়ে গেল। (Achcha, deri hoye gelo) - This literally translates to "Okay, it's late," and is a very casual way to acknowledge the delay.
* সরি, দেরী হয়ে গেল। (Sori, deri hoye gelo) - This is an informal way to say sorry, using the English word "sorry."
You can choose the appropriate phrase depending on the situation and your relationship with the person you are speaking to.