An $$ISMB$$ $$500$$ is used as a beam in a multi-storey construction. From the view point of structural design, it can be considered to be 'laterally restrained' when,

When designing steel structures, one must ensure that local buckling in webs does not take place. This check may not be very critical when using rolled steel sections because

Given reason for the following is not more than $$20$$ words

(a) A maximum permissible distance between lacing and battens in steel columns is
$$\,\,\,\,\,\,\,$$ usually specified.
(b) It is sometimes preferable to have unequal flange angle with the longer legs
$$\,\,\,\,\,\,\,$$ horizontal in plate girder.
(c) If two channel sections need to be used as a steel column, they may be connected
$$\,\,\,\,\,\,\,$$ 'face-to-face' rather than 'back-to-back'
(d) It is sometimes preferred to have a small gap between the web and the flange
$$\,\,\,\,\,\,\,$$ plate in a plate girder.
(e) A maximum permissible 'outstand may be specific for flange in built-up sections.

$$ISA$$ $$100 \times 100 \times 10mm$$ (cross sectional area $$ = 1903\,\,m{m^2}$$) is welded along $$A$$ and $$B$$ (Refer to figure in the below question) such that the lengths of the weld along $$A$$ and $$B$$ are $${l_1}$$ and $${l_2}$$ respectively. Which of the following is a possibly acceptable combination of $${l_1}$$ and $${l_2}$$