Question

There ... nothing I could do. so I
asked for help.
a) was
b) Wasn't
c) were​

Answer 1

there was nothing i could do. So i asked for help

como já tem "nothing" de negativo, você não pode usar "not" também, não pode fazer dupla negativa, por isso a resposta é "there was".

para usar o not teria que ser:

there wasn't a thing i could do OU there wasn't a thing i could have done.