In an alpha scattering experiment, few alpha particles rebounded because

Question

$(a)\;Most\; of\; the\; space\; in\; the\; atom\; is\; occupied \\ (b)\;Positive\; charge\; of \;the \;atoms\; very\; little \;space \\(c)\;The \;mass\; of \;the \;atom\; is\; concentrated\; in\; the\; centre \\(d)\;All \;the \;positive\; charge\; and\; mass\; of\; the\; atom\; is \;concentrated\; in\; small $