When distinguishing between a defined benefit pension plan $($DBPP$)$ and a defined contribution pension plan $($DCPP$),$ which statements are true?

$1.$The pension benefit from a DBPP can be calculated, while the benefit from a DCPP is unknown$\mathrm{.}2.$A DBPP holds more risk to the employee compared to a DCPP$\mathrm{.}3.$The pension adjustment for a DBPP and DCPP both rely upon the contributions of the employee and employer$\mathrm{.}4.$An employer knows the contributions required each year for a DCPP$,$ but the contributions for the DBPP are unknown.

a$.$

$3$ and $4.$

b$.$

$2$ and $3.$

c$.$

$1$ and $4.$

d$.$

$1$ and $2.$