Cast on 17 sts using 3.5mm needles and Yarn A.
Rows 1 to 31 Beg on a WS purl row, work in st st.
Row 32 K7, k2tog, K8. [16 sts]
Rows 33 to 39 Beg on a WS purl row, work in st st. Row 40 (K2tog) 8 times. [8 sts]
Break yarn and thread through rem sts. Pull tight to fasten.