In which series is the order of classification correct

Which of the following true? a_volcanoes and earthquakes often near the plate boundaries. b_volcanoes occur whereve there are tall mountains. c_earthquakes cause volcanoes in the same location to erupt violently d_volcanoes and earthquakes occur only where plates are colliding with each other

The clouds are grey and ground is wet. a quantitative b qualitative

The number at the end of an isotope’s name is the number.