Which of the following chlorophylls lacks a phytol tail?

Chlorophyll $a$ appears ------ in colour $\&$ chlorophyll $b$ appears ------ in colour on chromatogram :-

The approximate dimension of the chlorophyll porphyrin ring is

In the figure given below,the black line (upper) indicates the action spectrum for photosynthesis and the lighter line (lower) indicates the absorption spectrum of chlorophyll-$a$. Answer the following:
$(a)$ What does the action spectrum indicate? How can we plot an action spectrum? Explain with an example.
$(b)$ How can we derive an absorption spectrum for any substance?
$(c)$ If chlorophyll-$a$ is responsible for the light reaction of photosynthesis,why do the action spectrum and absorption spectrum not overlap?

In a chloroplast,chlorophyll is found in:

What is chlorophyll,which is essential for photosynthesis,chemically?