In "Quantum Gravity," the concept of "Loop Quantum Gravity" (LQG) is:
a) A theory that attempts to quantize gravity by describing spacetime as a network of discrete loops or quantum threads, leading to a granular structure at the Planck scale.
b) A theory that unifies all fundamental forces through higher-dimensional strings.
c) A model predicting the interaction between dark matter and dark energy.
d) A method for calculating the exact solutions of Einstein's equations in general relativity.