Which of the following are correct?

A rod is made of uniform material and has non-uniform cross section. It is fixed at both the ends as shown and heated at mid-section. Which of the following statements are not correct ?

A metal wire of length $L,$area of cross-section $A$ and young's modulus $Y$ is stretched by a variable force $F$ such that $F$ is always slightly greater than the elastic forces of resistance in the wire. When the elongation of the wire is $l$

A heavy block of mass $150 \mathrm{kg}$ hangs with the help of three vertical wires of equal length and equal cross-sectional area as shown in figure. Wire is attached to the mid-point (centre of mass) of block. Take $Y_2=2Y_1.$ For this arrangement mark out the correct statement(s).

The wires $A$ and $B$ shown in the figure are made of the same material, and have radii $r_A$ and $r_B$ respectively. The block between them has a mass $m.$ When the force $F$ is $mg/3,$ one of the wires breaks: