It should be Taurus.
Steady and earnest is the biggest feature of Taurus. She won't do anything she's not sure about. What you said,' He (she) answers questions seriously, and generally he (she) adopts his (her) answers in nine cases out of ten', which proves this point. Sometimes Taurus will be confused, stupid and do some unexpected things, and some extreme.
In short, it belongs to Taurus ~ ~ ~
Look at my signature and you will know that I am also a Taurus! !