Solve for $\theta$ in the range $0° \leq \theta \leq 360°$: $2\cos^2\theta - \cos\theta - 1 = 0$.

Factorising: (2cos θ + 1)(cos θ − 1) = 0, giving cos θ = −1/2 or cos θ = 1. cos θ = 1 gives θ = 0° (boundary, not listed) but the factored form cos θ = −1/2 gives θ = 120° and 240°, while cos θ = 1 gives θ = 0°. Re-checking: (2cos θ + 1)(cos θ − 1) = 0 gives cos θ = −1/2 → θ = 120°, 240° and cos θ = 1 → θ = 0°. However option A lists 60°, 180°, 300° which corresponds to cos θ = 1/2 and cos θ = −1. The correct factorisation gives cos θ = −1/2 (θ = 120°, 240°) and cos θ = 1 (θ = 0°, 360°). The answer is C: 0°, 120°, 240°.