Biles, who was arguably the greatest gymnast of all time, was expected to win multiple golds in Tokyo this year.
In option D, being is used wrongly to modify Biles.
A) Biles, who
was arguably the greatest gymnast of all time, was expected to win multiple golds in Tokyo
this year.
'Biles, who was' is wrong.
Biles is still alive and arguably the greatest gymnast of all time. Plus use of 'this year' emphasizes his presence in the present.
B) Biles, who
is arguably the greatest gymnast of all time,
was expected to win multiple golds in Tokyo
this year.C) Biles, who
were arguably the greatest gymnast of all time,
was expected to win multiple golds in Tokyo this year.
D) Biles,
being arguably the greatest gymnast of all time, was expected to win multiple golds in Tokyo this year.
E) Biles, who
is arguably the greatest gymnast of all time,
were expected to win multiple golds in Tokyo this year.
The answer is B.