There is optionally the substitution of long ā for the finals of jan , san and khan before the affix beginning with ya and marked with an indicatory k or ṅ,
Thus जायते or जन्यते (with यक्) जाजायते or जज्जन्यते (with यङ्) । So also सायते or सन्यते, सासायते, or संसन्यते, खायते, or खन्यते, चाखायते or चङ्खन्यते ॥ Before the vikarana श्यन् of the Fourth class, which is ङित् according to (l. 2. 4); the जा is always substituted for जन् by 7.3.79. No option is allowed there.,