a). The first shoe factory opened in 1760, but inexpensive shoes were not at all available to consumers for up until the industrial revolution of the 19th century.--–
‘for up until’, ‘not at all’ etc are unidiomatic expressions b). The first shoe factory had opened in 1760, but until the industrial revolution of the 19th century, inexpensive shoes were not at all available to consumers. ---
The main grouse against this choice is that, the element starting with ‘but’ through… ‘19th century’ should not have been rendered inessential by putting that under a parenthesis. If it is removed, the choice turns meaningless. Add to this tactical error, the use of ‘not at all’; a problem - ridden choice.c)The first shoe factory opened in 1760, however inexpensive shoes were not at all available to consumers until the industrial revolution of the 19th century ---
Grammatically, use of ‘however’ does require a comma after the word. d)The first shoe factory, though it opened in 1760, inexpensive shoes were not available to consumers up until the industrial revolution of the 19th century.---
Though ‘it’ is redundant. Secondly ‘up until’ is unidiomatic. e) The first shoe factory opened in 1760, but inexpensive shoes were not available to consumers until the industrial revolution of the 19th century.—
this is the correct choice One important issue about the past perfect ‘had opened’ and the simple past ‘opened’; IMO both are okay. Since the chronology is crystal clear by specifying the opening to 1760, and the subsequent happening to the 19th century, it is not incumbent that one needs to use the past perfect. However, it wouldn’t be a great error even if the past perfect is used.
_________________
Thank you Daagh for your time on GMAT Club and all your contributions! Thank you for everything you did!Your work will remain a great tribute to you here on GMAT Club!
-bb