What does the author imply by "Until now such bonds have largely been the preserv

What does the author imply by "Until now such bonds have largely been the preserve of rich-country is-suers" ( Line 3-4, Para.2) ?（ ）

[A] The catastrophe bonds are mainly reserved by rich countries.

[B] Only rich countries have the ability to issue the catastrophe bonds.

[C] Rich countries seldom issue the catastrophe bonds.

[D] Most of the catastrophe bonds are raised in rich countries.