The affix aṇ as well as the affix yuc come after the following verbs, forming feminine words - 1. cint 'to think' 2. pūj 'to worship' 3. kath 'to narrate' 4. kumb 'to cover' 5. carc 'to learn',
The force of च is to include the affix युच् into this sutra (see III. 3. 107). All these verbs belong to the Churadi or 10th class, and would have exclusively taken युच् by 3.3.107.
Thus चिन्ता 'thought'; पूजा 'worship'; कथा 'narration'; कुम्बा 'a covering', 'a thick petticoat'; चर्च्चा 'recitation'.
When the affix is युच्, the forms are चिन्तना &c. (VII. I. I).,