The reaction center that accepts light energy in Photosystem-$II$ is .........

During non-cyclic photophosphorylation,when electrons are lost from the reaction centre at $PS$ $II$,what is the source which replaces these electrons?

The first electron acceptor from an excited chlorophyll molecule of Photosystem-$II$ is .......

In the grana,the process $ADP + P_i = ATP$ is called .........

The first step in photosynthesis is

Assertion $(A) :-$ The whole scheme of transfer of electrons starting from $PS-II$ to $NADP^{+}$ is called $Z-scheme$.
Reason $(R) :-$ When all the carriers of this scheme are placed in sequence on a redox potential scale,they appear like $Z$.
In the light of the above statements,choose the correct answer from the options given below: