The European Solar Telescope (EST) is a 4.2-m telescope which has been redesigned with a fully integrated Multi-Conjugate Adaptive Optics (MCAO) into the optical path right after the EST primary mirror. The current baseline configuration considers four altitude Deformable Mirrors (DM) conjugated to 5, 9, 12 and 20 km above the telescope entrance pupil and an Adaptive Secondary Mirror (ASM) conjugated to the entrance pupil. The wavefront sensing will be performed by a set of correlation-based Shack Hartmann wavefront sensors (WFS) combining an on-axis High-Order WFS (HOWFS) to be used either in Single Conjugate AO (SCAO) to drive the ASM as well as operating simultaneously with a Multi-Directional WFS (MDWFS) to drive the MCAO. Beyond the current baseline configuration, different alternatives are currently being investigated both in the wavefront sensing strategy by evolving from a HOWFS+MDWFS into possibly a single High Order Multi Directional WFS (HOMDWFS) and/or wavefront sensors operating at different observing bands.