Python right answer shows as wrong

Question

I was looking at some code for a question game where the answers are read from a file, but when I run it, it tells me the answer is wrong even if it is right, have I typed it up wrong or is there something missing in the text file?

for line in lines:
question, rightAnswer = line.strip().split("\t")
answer = input(question + " ")
if answer.lower() == rightAnswer:
    print("Right!")
    numRight = numRight + 1
else:
    print("No, the correct answer is %s" % rightAnswer)

My text file is as follows:

How many strings does a guitar have?    Six
How many strings does a violin have?    Four
Are mandolin strings in pairs?  Yes

Answer 1

if answer.lower() == rightAnswer为if answer.lower() == rightAnswer.lower()