How to type matrices as options in a Multiple choice question paper?

Something like this?

documentclass{exam}
usepackage{amsmath}
newenvironment{smallpmatrix}{%
    bigl(begin{smallmatrix}%
    }{%
    end{smallmatrix}bigr)%
}
begin{document}
begin{questions}
    question Question with regular matrices.
    begin{oneparchoices}
        choice $begin{pmatrix} a & b  c & d end{pmatrix}$
        choice $begin{pmatrix} alpha & beta  gamma & delta end{pmatrix}$
    end{oneparchoices}
    question Question with smaller matrices.
    begin{oneparchoices}
        choice $begin{smallpmatrix} a & b  c & d end{smallpmatrix}$
        choice $begin{smallpmatrix} alpha & beta  gamma & delta end{smallpmatrix}$
    end{oneparchoices}
end{questions}
end{document}