Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_17 (engine VARCHAR, driver VARCHAR, tyre VARCHAR, constructor VARCHAR)

### Question ###
what is the engine when the tyre is d, the constructor is era and the driver is bob gerard?

### Accurate SQL ###

SELECT engine FROM table_name_17 WHERE tyre = "d" AND constructor = "era" AND driver = "bob gerard"