What a silly mistake has been done by you. Synonym for silly will be

Correct choice is B)

 'Silly' means stupid or foolish. E.g. It changed into a stupid mistake of leaving gas cylinder open. 'Abundant' means extra than enough. 'Absurd' means silly, stupid or unreasonable. 'Abstain' means to not do some thing. 'Accessory' means some thing brought to a gadget or to clothing. Thus, choice B is the perfect synonym for the word 'SIlly'.