Answer only A and C please.$($i$)$ Find the equilibria, $($ii$)$ determine the intervals where the growth rate is positive and where it is negative, and $($iii$)$ use your result to determine the stability if the equilibria.pls answer all parts.

a$)x^{\text{'}}=(1-x)(1-e^{-2x}).$

c$)R^{\text{'}}=\frac{3R}{1+R^2}-1.$

b$)y^{\text{'}}=y^4(1-y{e}^{-ay}),a>0.$

d$)z^{\text{'}}=\frac{1}{a^2+z}-lnz.$