Explanation:

• Flex-fuel vehicles (FFV): They have engines that can run on flexible fuel — a combination of petrol and ethanol, which can include up to 100% ethanol. 
• Flex Fuel Strong Hybrid Electric Vehicles (FFV-SHEV): When FFV is integrated along with strong hybrid electric technology, it is referred as FFV-SHEVs.

Strong hybrid is another term for full hybrid vehicles, which have the capability to run solely on either electric or petrol modes. 

• In contrast, mild hybrids cannot run purely on one of these modes and use the secondary mode merely as a supplement to the main mode of propulsion.

Hence both statements are correct.