$4.(3$ points$)$ Continuously compounded forward rates f$(0,1,2)$ and f$(0,2,3)$ are at $1\%$ an $1\mathrm{.}5\%,$ respectively. The rate f$(0,1,3)$ then equals to$...$

A$.1\%$

B$.1\mathrm{.}25\%$

C$.1\mathrm{.}5\%$

D$.2\mathrm{.}5\%$

E$.$ None of A to D is correct