Simplify $\; \large\frac{6m-3}{2mn} \;\div \; \large\frac{4m^{2}-1}{8m^{2}}$

Question

$(a)\;\large\frac{6m}{2m+1}\qquad(b)\;\large\frac{12m}{n(2m+1)}\qquad(c)\;\large\frac{12m}{2m+1}\qquad(d)\;\large\frac{6m}{n(2m+1)}$