Which variety of rice is an example of a naturally occurring mutation?

Consider the following four measures $(1-4)$ that could be taken to successfully grow chickpea in an area where bacterial blight disease is common.
$(1)$ Spray with Bordeaux mixture
$(2)$ Control of the insect vector of the disease pathogen
$(3)$ Use of only disease-free seeds
$(4)$ Use of varieties resistant to the disease
Which two of the above measures can control the disease?

Which of the following steps in plant breeding is very tedious and time-consuming?

"Jaya" and "Ratna" developed for the Green Revolution in India are varieties of

The "Pusa Komal" variety of cowpea, which was developed by hybridization and selection, is primarily resistant to which of the following?

The conventional method of breeding for resistance includes:
$I$. Screening the germplasm for resistant sources
$II$. Hybridization of selected parents
$III$. Selection and evaluation of the hybrids
$IV$. Testing and release of new varieties
Choose the correct option.