i. $\large{\frac{r}{s}+\frac{s}{s} < \frac{t}{v}+\frac{v}{v}}$ $\implies$ $\large{\frac{r}{s}+1 < \frac{t}{v}+1}$ $\implies$ $\large{\frac{r}{s} < \frac{t}{v}}$ $\color{green}{[\text{Verdadeiro}]}$ ii. $\large{\frac{r}{r+s} = \frac{1}{1+\frac{s}{r}}< \frac{t}{t+v} = \frac{1}{1+\frac{v}{t}}}$ $\implies$ $1+\frac{s}{r} < 1+\frac{v}{t}$ $\implies$ $\large{\frac{r}{s} < \frac{t}{v}}$ $\color{green}{[\text{Verdadeiro}]}$ iii. $\large{\frac{r}{s} < \frac{r+t}{s+v}}$ $\implies$ $rs + rv < rs + st$ $\implies$ $\large{\frac{r}{s} < \frac{t}{v}}$ $\color{green}{[\text{Verdadeiro}]}$ iv. $vr + vt < rs + st$ $\implies$ $r(v-s) < t(s-v)$, se $v=s$ , $0<0$ $\color{red}{[\text{Falso}]}$ Há $3$ relações corretas.$$\text{Alternativa } \mathbb{(D)}$$