In the wild, a male canary sings primarily to attract the female canary so that it can find a mate to breed with. The female canary can imitate a male very well at singing. The sounds produced by the female canary match the male so well that it is sometimes difficult to differentiate between the two and many females are sold as male canaries. Females that have started to sing usually stop doing that after the first baby molts. They may sing sporadically but hens naturally do not require to sing.
Male canaries usually start to sing from when they are 6 months old and though they can continue to sing till the age of 5-10, they are too old after they turn 3 and find it very difficult to sing.
Birds also do not sing when they molt once in a year. This could be for a period of 1-2 months.
The most likely answer to your query is option b, a female canary does not sing naturally.