As Noted in Strategy Highlight 8

As noted in Strategy Highlight 8.3,in 2008 ExxonMobil reported the highest profits ever recorded by any company.Exxon receives the majority of its profits from petroleum-based products.Due to the political and regulatory climate and the global movement toward cleaner energy sources,Exxon purchased the natural gas company XTO Energy in 2009 as a low-carbon alternative to petroleum.Exxon then became the world's largest producer of natural gas.All of the following are true about Exxon's strategic move EXCEPT:

A) Exxon horizontally integrated when it purchased XTO Energy.
B) Exxon is using its core competencies for corporate diversification.
C) Exxon is pursuing an unrelated diversification strategy.
D) Exxon is investing in more ecologically sound resources.