A function $\mathrm{f}$ is constant from set $\mathrm{A}=\{1,2,3\}$ onto set $\mathrm{B}=\{\mathrm{a}, \mathrm{b}, \mathrm{c}\}$ such that $\mathrm{f}(1)=\mathrm{a}$, then the range of $\mathrm{f}$ is
(1) $\{\mathrm{a}, \mathrm{c}\}$
(2) $\{\mathrm{a}\}$
(3) $\{\mathrm{a}, \mathrm{b}\}$
(4) $\{\mathrm{a}, \mathrm{b}, \mathrm{c}\}$