Answer:
[tex]\boxed{\text{C) 15}}[/tex]
Step-by-step explanation:
Let's examine the differences between consecutive terms
[tex]\begin{array}{cc}\textbf{Term} & \textbf{Diff.} \\90 & \\& 5 \\85 & \\& 10 \\75 & \\& 20 \\55 & \\& \mathbf{40} \\\mathbf{15} & \\\end{array}\\\text{The difference doubles with each consecutive term.}\\\text{If the pattern continues, the next term will decrease by 40.}\\\text{The next term in the series will be $\boxed{\mathbf{15}}$.}[/tex]
