Various concentrations of an antibiotic are incubated with $5mL$ of a culture of $E$ coli. Based on the results below, what is the MIC for this antibiotic? Antibiotic concentration $($mcg$/$mL$)$ Visible growth $8N4N2$ Y $1Y1mc\frac{g}{m}L2mc\frac{g}{m}L4mc\frac{g}{m}L8mc\frac{g}{m}L$