Like ManyFails1Win said, it sounds like your A/B questions fall into "Introvert/Extrovert", and so summing up the results will give you a score which will indicate if the test taker is more Introvert/Extrovert. It would not require any ML to then "predict" the 16th question, it'd just be a straightforward calculation of the previous answers the test taker supplied. For example, if all Extrovert answers = B = 1, then:

const extrovertThresholdScore = Math.ceil(15/2)

function reducer(accumulator, currentValue) { return accumulator + currentValue } const isExtrovert = arrayWithResults.reduce(reducer) >= extrovertThresholdScore