Significant and its equivalent in a sentence

[thanhnhankaka]

Hi all,
I am really in two minds about this particular sentence:
"There are no significant differences between the two issues"
Which word (and only one word) has the closest meaning with significant in this sentence?
A. meaningful B. important C. big
OALD's definition: large and important enough to have an effect or to be noticed.
The cause for my confusion lies in the word big since it also means important and large (figuratively or literally, such as big decision, big question...). Furthermore, is it me or does anyone else think meaningful is also worth considering in this particular sentence?

[thanhnhankaka]

More than 50 views and no reply? Please all, tell me something i don't know, or something i missed. That would be highly appreciated.

[5jj]

An important word in the OALD's definition is 'enough'. It's not just 'large', but large enough to be meaningful.

[thanhnhankaka]

Finally, first reply, thank you so much. Although i must say i don't get your point there @5jj. It would be nice if you could provide more details.
OALD defines big as important (though informal, the 3rd meaning). It further perplexed me now. Most of my friends went with important for that was the meaning they were taught. I just want to know why not big? The question itself did not imply that we must choose the academic word for this, so that should not be the reason. (Did i over-think this question?)
I want to thank you all in advance.

[5jj]

big/large enough. My car is small, but it's big enough for my needs.

There is no idea at all of 'importance' in 'big' there.