Which of the following is a sensible method of reducing spam submissions to Web forms you create?

Implementing CAPTCHA is a widely recognized and effective method for reducing spam submissions to web forms. CAPTCHA stands for "Completely Automated Public Turing test to tell Computers and Humans Apart." It is designed to differentiate between human users and automated bots that may be programmed to send unsolicited or spam submissions.

CAPTCHA achieves this by presenting challenges that are difficult for computers but simpler for humans to solve, such as identifying distorted text, selecting images that meet certain criteria, or answering simple questions. By requiring users to complete a CAPTCHA challenge before submitting their forms, you significantly decrease the likelihood of spam submissions, as most spam bots are unable to adequately complete these challenges.

Other methods listed, such as using drop-down menus or allowing only certain email domains, may have limited effectiveness in completely preventing spam. While these strategies can offer some control over the data being submitted, they do not inherently distinguish between human users and automated scripts. Requiring phone numbers may result in some level of verification, but it could also discourage legitimate users from completing the form if they feel it's too intrusive or tedious.