Should an average proton or electron at 15 million degrees Kelvin be treated by relativistic mechanics?

A. Yes, because at such high temperatures, the particles attain significant fractions of the speed of light, and relativistic effects become important.
B. No, because at 15 million degrees Kelvin, the relativistic effects on particles like protons and electrons are negligible.
C. Yes, but only for electrons, as protons are too massive to experience significant relativistic effects at this temperature.
D. No, because relativistic mechanics only apply to extremely high speeds or strong gravitational fields, which are not relevant at 15 million degrees Kelvin.