The pattern of electrons in their atoms causes nickel and certain other metals to be magnetic. The correct option is B. The bound electron in elements occur in pairs. Some element have unpair bound electrons which set up tiny magnet effects inside the atoms. When such unpaired electrons are plenty in an atom, they cause the element to be magnetic in nature. For the second question, the correct option is A. Bar magnetic magnetic fields are strongest at both poles, that is, at the south and the north poles.
