Later is an adverb of your time and hence cannot be employed in the context of two people, this word is employed in sentences like: ‘I will move to the market later this evening’ , here there's a awfully clear mention of your time frame. Therefore, the choice a is inaccurate.
According to the foundations of Degrees of Adjective or comparison, when two entities are being compared, the comparative form is employed, during this case, the three degrees of comparison would be, Versatile (positive degree), More Versatile( comparative degree) and Most Versatile (superlative degree). So, with this rule, option c is additionally incorrect.
‘Latest’ means: of the foremost recent date or something novel, which completely eliminates the d option.
With the above deductions and considering the foundations mentioned, option b is correct because the appropriate degree of an adjective is employed together with the term latter.