Which one of the following does not signify a battle tank?

Which one of the following does not signify a battle tank?

T-55
T-155
T-72
T-90
This question was previously asked in
UPSC CDS-2 – 2016
T-155 does not signify a battle tank.
– T-55, T-72, and T-90 are well-known designations for series of Soviet and later Russian main battle tanks.
– T-155 is not a standard designation for a widely recognized main battle tank. The T-15 Armata is a Russian heavy infantry fighting vehicle, and the T-14 Armata is the new Russian main battle tank. T-155 Fırtına is a Turkish self-propelled howitzer.
Military equipment designations follow specific nomenclature systems. While similar numbers might exist for different types of vehicles or different countries, T-55, T-72, and T-90 are unequivocally identified as battle tanks in the global context.