From the sequence:
[tex]\begin{gathered} a_1\text{ = }\frac{1}{3} \\ a_2\text{ = -1}\frac{1}{2} \\ a_3\text{ = -3}\frac{1}{3} \\ a_4\text{ =-5}\frac{1}{6} \end{gathered}[/tex]If we take the difference between successive session:
[tex]\begin{gathered} a_2-a_1\text{ = }\frac{-11}{6} \\ a_3-a_2\text{ = }\frac{-11}{6} \\ a_4-a_3\text{ = }\frac{-11}{6} \end{gathered}[/tex]We can thus conclude that:
[tex]\begin{gathered} a_{n+1\text{ }}=a_n\text{ - }\frac{11}{6} \\ a_{n+1\text{ }}=a_n\text{ -1}\frac{5}{6},\text{ where n = 1,2,3,4} \end{gathered}[/tex]This corresponds to option B