In 2009,ExxonMobil Bought XTO Energy,a Natural Gas Company,for $31 Billion

In 2009,ExxonMobil bought XTO Energy,a natural gas company,for $31 billion.XTO Energy is known for its core competency to extract natural gas from unconventional places such as shale rock-the type of deposits currently being exploited in the United States.ExxonMobil hopes to leverage its core competency in the exploration and commercialization of oil into natural gas extraction.Based on this example,ExxonMobil is engaging in

A) unrelated-linked diversification.
B) unrelated-constrained diversification.
C) related-linked diversification.
D) related-constrained diversification.