How to configure reCaptcha, so its always display number as display text in NopCommerce?

Question

I just need to configure reCaptcha, so it is only display numbers as display text,

no word as display text.

I need do this configuration in Nop

Answer 1

Google uses "advanced risk analysis techniques, actively considering the user’s entire engagement with the CAPTCHA" to determine how difficult of a puzzle the user deserves. So there is not configuration setting and most users get simple numbers by default.

Source: http://googleonlinesecurity.blogspot.com/2013/10/recaptcha-just-got-easier-but-only-if.html

I've noticed when testing for a while it starts to get suspicious of me and throws some that are near impossible to get right. Then a few days later it's nicer to me again.