$\text{M20}$ concrete as per $\mathrm{IS~} 456: 2000$ refers to concrete with a design mix having ____________
- an average cube strength of $20~ \mathrm{MPa}$
- an average cylinder strength of $20~ \mathrm{MPa}$
- a $5$-percentile cube strength of $20~ \mathrm{MPa}$
- a $5$-percentile cylinder strength of $20~ \mathrm{MPa}$