When magma experiences assimilation or partial melting it becomes:

a. more mafic

b. more felsic

c. no change

b. more felsic

Explanation:

The sequnce of crsytallization of magma  as , first is the ultramafic which is at at very high temperature ,  then is mafic at intermediate temperature , and felsic at lowest lowest temperature , at the final stage .

Hence , the composition of earth beneath the surface is like mafic while the surface has felsic .

When the crystallizing magma is assimilated  or contaminated with the crystal rock and then the magma enhances the light color or the felsic minerals added into magma due to the assimilation of the crystal rocks .

Therefore , the magma increases the felsic nature via assimilation .

Now , When a rock undergoes partial melting , then low temperature or light color minerals released first into melts and hence , becomes more felsic .