According to the law of universal gravitation, the force of gravity between two objects is inversely proportional to the square of the distance between them. Therefore, the correct answer is:
B Inversely proportional to the square of the distance between them.
The law is commonly expressed with the formula:
\[ F = G \frac{m_1 m_2}{r^2} \]
where \( F \) is the force of gravity, \( m_1 \) and \( m_2 \) are the masses of the two objects, \( r \) is the distance between the centers of the two objects, and \( G \) is the gravitational constant.