Design Moment Capacity for a Rectangular RC Beam

Given:

$f_c^{\text{'}}=30$MPa

$f_y=420$MPa

Clear cover $=40mm$

Stirrup size $=10mm$

Beam dimensions: Width $b=300mm,$ total depth $h=500mm$

Steel reinforcement: $6$ bars of $20mm($diameter$)$

Determine the design moment capacity $M_{}$ for the beam.