b. He made up his mind based on his annoyance. This is the correct answer.
He is Victor , the main character from Frankestein. He gets annoyed at the people who have passed onto him " magical" information - alchemy- about natural phenomena. "...these men disinclined me to pursue ..."; "...suddenly grew despicable..." , these quotations exemplify Victor's negative opinion about the alchemists. " In this mood of mind I betook myself to the mathematics and ...", in this quotation he says he has decided to study rational subjects.
These answers are not right:
a. He made up his mind after careful consideration ( Victor does not consider alchemy but criticises it).
c. He made up his mind by getting good advice. ( Victor makes up his mind by himself when he hears a scientist talk about electricity).
d. He made up his mind to quit working altogether. ( On the contrary, Victor starts to study very hard).