JEE Main 2019 Physics question

A particle 'P' is formed due to a completely inelastic collision of particles 'x' and 'y' having de-Broglie wavelengths '' and '' respectively. If x and y were moving in opposite directions, then the de-Broglie wavelength of 'P' is:

• (A)
• (B)Correct
• (C)
• (D)