Which of the following is the least productive ecosystem?

Which of the following ecosystems has the highest productivity?

The biomass produced by plants in the oceans accounts for approximately how much of the total global primary productivity (in $\%$)?

Secondary productivity is defined as ...

Match the Column-$I$ with Column-$II$ and choose the correct option.

Column-$I$	Column-$II$
$(a)$ $\text{NPP}$ of ocean	$(i)$ $115$ billion tons
$(b)$ Annual $\text{NPP}$ of the whole biosphere	$(ii)$ $170$ billion tons
$(c)$ $\text{NPP}$ of terrestrial ecosystem	$(iii)$ $55$ billion tons
$(d)$ Secondary productivity	$(iv)$ Heterotrophs

Which ecosystem has the highest gross primary productivity?