The correct answer is $\boxed{\frac{1}{2}}$.
The tidal force is the difference between the gravitational forces exerted by two objects on a third object. The magnitude of the tidal force is proportional to the product of the masses of the two objects and inversely proportional to the cube of the distance between the two objects and the third object.
The Sun is about 390 times more massive than the Moon, but it is also about 400 times farther away from Earth. This means that the gravitational force exerted by the Sun on Earth is about 0.012 times the gravitational force exerted by the Moon on Earth.
The tidal force exerted by the Sun on Earth is therefore about 0.012 times the tidal force exerted by the Moon on Earth. This means that the solar tidal force divided by the lunar tidal force is about $\frac{1}{2}$.
Option A is incorrect because the solar tidal force is not $\frac{1}{3}$ of the lunar tidal force. Option B is incorrect because the solar tidal force is not $\frac{1}{2}$ of the lunar tidal force. Option C is incorrect because the solar tidal force is not $\frac{3}{4}$ of the lunar tidal force. Option D is incorrect because the solar tidal force is not $\frac{5}{4}$ of the lunar tidal force.