Final answer:
HTML5 semantic elements are partially supported across different browsers, with modern browsers generally offering good support, while older versions may lack complete support. Developers use polyfills to address support issues.
Step-by-step explanation:
The correct answer to the question “HTML5 semantic elements are supported in all browsers.” is c) Partially true. While most modern web browsers support the bulk of HTML5 semantic elements, the level of support can vary depending on the browser version. Older versions of web browsers may not fully support all HTML5 features. For example, elements such as <article>, <section>, and <nav> are universally supported by all current browser versions, but more obscure semantic elements may have inconsistent support.
Developers often use polyfills or script libraries to ensure functionality across different browsers, addressing the gaps in support for HTML5 semantic elements. Hence, the statement is only partially true as the support highly depends on the version and type of browser being used.