Doubt in identifying support or contrast

In the above question, i didn’t get should i choose “semicolon” or “however”.
I chose “semicolon” as it’s first but greg considered “however”.
Can you please explain why “however” was chosen?

Its not a matter of what comes first, it has to do with preference.
Semicolons and commas are generally weak support words. “However” is a strong contrast hence it will overpower the semicolon.

Thank you Hem for the response.
Can you share the preference list which contains strong and weak support words?

If you go to the support/contrast list on the website:

There’s a section called less obvious support/contrast words

In this question, which blank do you need help picking a support/contrast word for?