What is the minimum frequency ratio, $r,$ that a fixed$-$base resonator must attain to ensure that no more than $1000$ lbs of load be transmitted to the base from a harmonic load of $F(t)=(3000lbs)cos50t$

a$)r_{\text{m}\text{i}\text{n}}=\frac{1}{\sqrt[\phantom{2}]{2}}$

b$)r_{\text{m}\text{i}\text{n}}=\frac{1}{\sqrt[\phantom{2}]{3}}$

c$)r_{\text{m}\text{i}\text{n}}=\frac{1}{3}$

d$)r_{\text{m}\text{i}\text{n}}=2$

e$)r_{\text{m}\text{i}\text{n}}=3$