After conducting a risk assessment, it is found that the required risk reduction factor for a low-demand safety function is 85. Which of the following safety functions (with full certainty that is practical) can be used to reduce the risk to tolerable levels within reason? Select all that applies. A pneumatic based safety function which is PLa A hydraulic based safety function which is PLd A SIL 1 E/E/PE safety function A SIL 2 E/E/PE safety function A SIL 3 E/E/PE safety function