JEE Main Physics question

A boy begins to walk eastward along a street in front of his house, and the graph of his displacement from home (distance east, in metre, vs time, in min) is shown: rising linearly from 0 to 40 m over 0–5 min, constant at 40 m from 5–10 min, then declining past zero to about m by around min. His average speed for the whole time interval is nearly

• (A)8 mmin
• (B)6 mminCorrect
• (C) mmin
• (D)2 mmin