28-19: Plankton generally thrive in areas of the ocean with
sufficient concentrations of certain nitrogen compounds near the
surface where plankton live. Nevertheless, some areas, though rich
in these nitrogen compounds, have few plankton. These areas have
particularly low concentrations of iron, and oceanographers
hypothesize that this shortage of iron prevents plankton from
thriving. However, an experimental release of iron compounds into
one such area failed to produce a thriving plankton population,
even though local iron concentrations increased immediately.
Which of the following, if true, argues most strongly against
concluding, on the basis of the information above, that the
oceanographers’ hypothesis is false?
A: Not all of the nitrogen compounds that are sometimes found in
relatively high concentrations in the oceans are nutrients for
plankton.
B: Certain areas of the ocean support an abundance of plankton
despite having particularly low concentrations of iron.
C: The release of the iron compounds did not increase the supply of
nitrogen compounds in the area.
D: A few days after the iron compounds were released, ocean
currents displaced the iron-rich water from the surface.
E: The iron compounds released into the area occur naturally in
areas of the ocean where plankton thrive.
求问此题的思路.
我的问题是：
1. 被问题搅糊涂：Which of the following, if true, argues most
strongly against concluding, on the basis of the information above,
that the oceanographers’ hypothesis is false? 文中先出现了
oceanographers' hypothesis, 然后author提出疑问反对此 hypothesis. 问
题问的是不是反对author 的结论，也就是相当于削弱题？
2. C错在哪里？ | 
