Sentence Correction

In 1860, the Philological Society launched its effort to create a dictionary more comprehensive than the world had ever seen; although the project would take more than 60 years to complete, the Oxford English Dictionary had been born.

1- would take more than 60 years to complete, the Oxford English Dictionary had been

2- took more than 60 years to complete, the Oxford English Dictionary was

3- would take more than 60 years to complete, the Oxford English Dictionary was being

4- would take more than 60 years to complete, the Oxford English Dictionary was

5- took more than 60 years to complete, the Oxford English Dictionary was about to be

IMO B

hey_thr67 wrote:In 1860, the Philological Society launched its effort to create a dictionary more comprehensive than the world had ever seen; although the project would take more than 60 years to complete, the Oxford English Dictionary had been born.

1- would take more than 60 years to complete, the Oxford English Dictionary had been

2- took more than 60 years to complete, the Oxford English Dictionary was

3- would take more than 60 years to complete, the Oxford English Dictionary was being

4- would take more than 60 years to complete, the Oxford English Dictionary was

5- took more than 60 years to complete, the Oxford English Dictionary was about to be

Since we are describing a project that began in 1860 and predict that it takes 60 years for completion, would should not be used. Thus, A, C and D can be eliminated.

Between B and E,

Both follow the Although X,Y idiom properly but E lacks parallelism considering the tense of X and Y.

Thus, IMO B.

Please correct in case I am wrong and share the source of the question.