Instruction: Evaluate each product title in the given list, assess its relevance to the given query, and then arrange the products in descending order of relevance, with the most relevant product at the top of the ranked list.

Input:
Query: 30 gallon gas water heater
Product list:
A: Rheem PROE6 1 RH POU Professional Classic Residential 6 Gallon Electric Point-of-Use Water Heater
B: Camplux Tankless Water Heater Natural Gas,High Efficiency Natural Gas Tankless Water Heater with Fahrenheit Digital Display, 3.18 GPM On Demand Water Heater for 2-3 Persons Bathroom Indoor Use,White
Answer: B,A