According to International Insight $-$ ExxonMobil Corporation Is LIFO Fair? in Chapter $7$ of the text, why isn't the net income of a foreign oil company like BP directly comparable to ExxonMobil's?

The income statement of foreign company's are in a different currency.

ExxonMobil uses LIFO and international accounting standards do not allow the use of LIFO.

ExxonMobil is focusing on renewable energy.

$BP$ is focusing on renewable energy.