Which of the following solutions is basic?
a) [OH-] = 1.0 × 10⁻⁷M
b) [H3O+] = 1.0 × 10⁻¹⁴M
c) [H3O+] > 1.0 × 10⁻⁷ M
d) [OH-] < 1.0 x 10 ⁻⁷ M