Algebra-2

Question Analysis
This problem assesses the student's ability to apply Descartes' Rule of Signs to determine the possible number of positive real roots of a polynomial with a higher degree.

Key Concept Explanation
Descartes' Rule of Signs states that the number of positive real roots of a polynomial is equal to the number of sign changes in the sequence of its coefficients, or less than that by a multiple of 2.

Step-by-step Solution
1. Identify the coefficients of the polynomial: 2, -5, 3, -7, 4, -1, 8
2. Count the sign changes in the sequence of coefficients:
From 2 to -5: 1 change