It is interesting to see the usage in the NYT. I see instances where a comma is used. I see just as many where it isn't. With one exception, every article printed prior to 1950 appears to use "because, although." Removing the comma appears to be a (relatively) new convention.

If students are confused, it should always be possible to restructure the sentence to separate the two words.

"Although the narrator does say she hates lemons, choice A is incorrect because this is not the main idea of the passage."

It is interesting to see the usage in the NYT. I see instances where a comma is used. I see just as many where it isn't. With one exception in twenty, every article printed prior to 1950 appears to use "because, although." Removing the comma could be a (relatively) new convention.

If students are confused, it should always be possible to restructure the sentence to separate the two words.

"Although the narrator does say she hates lemons, choice A is incorrect because this is not the main idea of the passage."