The north atlantic right whale was classified as an endangered species in 2015. a major cause of death for these whales is collisions with shipping vessels. several measures have been enacted to prevent such collisions in regions with a high abundance of right whales. in 2002 and 2006, shipping vessel lanes were rerouted around some of these regions. in 2008, speed restrictions were placed on the shipping vessels that were permitted to travel through these regions.

the graph below shows the estimated abundance of north atlantic right whales from 1990 to 2015. the years in which these measures were enacted are marked on the graph. modified from pace et al., 2017. ecology and evolution 7(21): 8730 - 8741. licensed under cc by 4.0. what conclusion is best supported by the data in the graph?

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a. modifying shipping lanes is the most effective method of encouraging population growth in right whales.

b. limiting shipping vessel speeds is the most effective method of preventing population decline in right whales.

c. changes to vessel speeds and lanes have been effective in preventing population declines in the right whale population, and no further actions are needed.

d. while changes to vessel lanes and speeds may have been beneficial to right whales, additional actions are needed to prevent population declines.