Final answer:
There is no irrefutable evidence of life beyond Earth. The exploration of Europa and Mars seeks signs of potential habitability and past life, but as of now, no direct evidence has confirmed life outside our planet.
Step-by-step explanation:
The only place outside of Earth where there is irrefutable evidence for (ancient, microbial) life is E) None of the above-there is no irrefutable evidence for life beyond Earth. While many scientists believe that Europa is a likely place to find life due to its sub-ice oceans, and Mars has a history that includes liquid water which may have supported life, no direct evidence of past or present life has been found to date. NASA's upcoming mission, Europa Clipper, aims to gather more data on Europa's ocean and ice crust, possibly revealing signs of microbial life. Furthermore, the ongoing exploration of Mars follows the 'follow the water' principle to look for potential habitable conditions or evidence of past life.