The lowest frequency!

--- Quote Start ---

but i try whith sample rate 10MHz and filter type is bandpass have cutoff are 200Hz and 300Hz

--- Quote End ---

That's not impossible in theory, but practically, cause you would require several thousand FIR taps in this case. Just consider, that the filter must have at least a length equivalent to several periods of the characteristic filter frequencies. You can either build IIR filters, although they need a rather large coeffecient length and a lot of extra fractional bits, but they are basically feasible for such extreme frequency ratios. Or use a decimation before the filter.