Explanation:

Correct Option: (c) Explanation:  Both statements are correct Supplementary notes: Einsteinium  A team of scientists at the Berkeley Lab has recently reported some of the properties of element 99 in the periodic table called “Einsteinium”, named after Albert Einstein.  The team worked with einsteinium-254, one of the more stable isotopes of the element that has a half-life of 276 days.  The most common isotope of the element, einsteinium 253 has a half-life of 20 days.  Because of its high radioactivity and short half-life of all einsteinium isotopes, even if the element was present on Earth during its formation, it has most certainly decayed. This is the reason that it cannot be found in nature and needs to be manufactured using very precise and intense processes.  It was discovered in 1952 in the debris of the fi rst hydrogen bomb (the detonation of a thermonuclear device called “Ivy Mike” in the Paci fi c Ocean).  Since its discovery, scientists have not been able to perform a lot of experiments with it because it is diffi cult to create and is highly radioactive. Therefore, very little is known about this element.  The element is also not visible to the naked eye and after it was discovered, it took over nine years to manufacture enough of it so that it could be seen with the naked eye