can you please show a STEP BY STEP SOLUTION on how this is solved ( and if it is not a CFG then why is it not a CFG-show with steps please)

Are the following languages context-free or not? If yes, specify a context- free grammar in BNF notation that generates the language. If not, give an informal argument. { a"brend" l n > 0, m > 0 }, with alphabet -{a, b, c, d}