Arctic terns, being true long-distance migrants, they nest in coastal wetlands of northern Europe but fly south for thousands of miles to spend the European winters in Antarctica.
A Arctic terns, being true long-distance migrants, they nest in coastal wetlands of northern Europe - 2 subjects - Arctic terns and they . Being is awkward here
B Arctics terns are true long-distance migrants, nesting in coastal wetlands of northern Europe, - Wrong modification using Verb- ing . Illogical sentence - usage of but
C Being that they are true long-distance migrants, arctics terns nest in coastal wetlands of northern Europe - Being that they are is redundant and awkward
D Nesting in coastal wetlands of northern Europe, arctic terns are true long-distance migrants - Grammatically correct , but illogical meaning -because of the "but" conjunction
E True long-distance migrants, arctics terns nest in coastal wetlands of northern Europe - Correct
Answer E