Farmers in a particular region were concerned that premature yellowing of leaves of a pulse crop might cause decrease in the yield. Which treatment could be most beneficial to obtain maximum seed yield?

(1) Application of iron and magnesium to promote synthesis of chlorophyll

(2) Treatment of the plants with cytokinins along with a small dose of nitrogenous fertilizer

(3) Frequent irrigation of the crop

(4) Removal of all yellow leaves and spraying the remaining green leaves with 2, 4, 5- trichlorophenoxy acetic acid