user: ### NOW ANSWER:
Question: What is the entry for Lower index MJ/ Nm 3 for the row that has an Upper index Kcal/ Nm 3 larger than 19376, for LPG, and an Upper index MJ/ Nm 3 smaller than 86.84?
Columns: ['Fuel gas', 'Upper index Kcal/ Nm 3', 'Lower index Kcal/ Nm 3', 'Upper index MJ/ Nm 3', 'Lower index MJ/ Nm 3']
Types: ['text', 'real', 'real', 'real', 'real']
Sample row: ['Hydrogen', 11528.0, 9715.0, 48.23, 40.65]
SQL:

assistant: SELECT AVG("Lower index MJ/ Nm 3") FROM "Table" WHERE "Upper index Kcal/ Nm 3" > 19376.0 AND "Fuel gas" = 'LPG' AND "Upper index MJ/ Nm 3" < 86.84;