The pre-emergence herbicides recommended for groundnut are
1. Alachlor 2. Pendimethalin 3. Diuron 4. Atrazine

Correct option is B

Alachlor is a recommended pre-emergence herbicide in groundnut for controlling annual grasses and some broad-leaved weeds.
Pendimethalin is also widely recommended as a pre-emergence herbicide in groundnut.
Diuron is mainly recommended for crops like sugarcane and cotton, not groundnut.
Atrazine is primarily used in maize and sorghum crops.
Hence only Alachlor and Pendimethalin are suitable.
Therefore option (b) is the correct answer.