Select what is TRUE about restricted Boltzmann machines:

they are Boltzmann machines, but with no connections between nodes in the same layer

each node in the first layer has a bias

they reconstruct data by making several forward and backward passes between visible and hidden layers

same weights and bias are used going forward $($from visible layer to hidden layer$)$ and backwards $($from hidden layer to visible layer$)$

as they are based on a stochastic process, the objective function is to maximise the probability of input data being drawn from the reconstructed data distribution

all of the above