The number of `alpha` and `beta`- emitted during the radioactive decay chain starting from `._(226)^(88) Ra` and ending at `._(206)^(82) Pb` is
A. `3alpha` and `6beta^(-)`
B. `4alpha` and `5beta^(-)`
C. `5alpha` and `4beta^(-)`
D. `6alpha` and `6beta^(-)`
