oops this is hard. B is probably the best.

here is what I think

A. Though X, Saturn's rings.... Here the contrast is wrong. Also
I think "in fact" is an expletive modifier and that modifier is redundant.

B. Best among the 4 but it still has the expletive modifier.

C ", though when viewed....." is a ackward and run on.

D. "closer viewing" is ackward. Could have be replaced by "on closer view" or something like that.

E. Changes the meaning of the sentence. It says that "the main rings are composed of X IF viewed up close" but if they are not viewed up close, the main rings are NOT composed of X. The rings are composed of thousands of icy ringlets whether one views upclose or sees from a distance.

Pls let me know if I have messed something.

This is modifier + meaning clarity question.

All the options but D, tell that Saturn's rings are composed differently depending how you look at them.

But the real idea the sentence trying to convey is how they look. Not what they are made of.

Choose (D)

stubbornp wrote:Which one is best?please explain

i go with D as well

couple of mistakes which i found are;

"appears to be" is redundant
"Though" - one cant start a Main clause with it unless u wanna use it for contradiction.

D makes all these correct and the phrase "closer viewing reveals" clearly indicates that the close viewing only reveals and not causes the composition of the rings.

Additional inputs

Though-If is an incorrect construction

In second part of option D, there is "viewing" because of which don't you think that the parallelism goes awry because there is "viewed" in the first part of the sentence.

I would go with D as well .. It took more than 2 minutes though.

- pradeep

IMO B.

I don't think "closer viewing" is correct