If x² - y² + 2hxy + 2gx + 2fy + c = 0 is the locus of points such that it is equidistance from the lines x + 2y - 8 = 0 and 2x + y + 7 = 0 then value of h + g + f + c is
a) 15
b) -15
c) 20
d) -20