Read these sentences from the text: "[The manikin said,] 'What will you give me if I spin the straw for you this time also?'

"'I have nothing left that I could give,' answered the girl.

"'Then promise me, if you should become Queen, your first child.'

"'Who knows whether that will ever happen?' thought the miller's daughter; and, not knowing how else to help herself in this strait, she promised the manikin what he wanted, and for that he once more span the straw into gold."

What does the phrase "not knowing how else to help herself in this strait" mean based on these sentences?

a
not knowing how else to solve her problem
b
not knowing how to break a promise
c
not knowing how to act like a Queen
d
not knowing how to spin straw into gold